Aliasing only had a bit of ad-hoc support in rebar3, and various issues
have encountered problems related to the package names not mapping
properly with the application name. One such issue is
https://github.com/erlang/rebar3/issues/1290

The problem has been hard to find because it only impacts transitive
dependencies (not top-level ones) of other packages. The root cause for
this is that the application name was not being tracked by rebar3's internal
index, only the package name and its version were.

When a given application was a package app, the data for the application
name would be reconstructed from the lock file, but only if it were a
top-level app or a dependency of a source application where parsing the
lock file is necessary to know what comes next.

When a transitive dependency of a package dependency was fetched, we
instead read its dependencies directly from the in-memory package index
within rebar3. This caused us to only read the package name and version,
and lost all information regarding application name. This worked fine
for most cases since for the vast majority of packages, the package name
matches the app name, but failed for all aliases, which would then be
moved to directories that wouldn't match the app name.

This in turn broke some aspects of code analysis (in Dialyzer), or other
functionality relying on static paths, such as including .hrl files from
dependencies.

This patch reformats the internal storage format of dependencies to
align with the internal one used by rebar3, so that the app name can be
carried along with the package name and its version.

The fix can only work once `rebar3 update` is called so the index is
rebuilt internally, and will the file cached on disk will be
incompatible with older rebar3 versions.

Currently, the following is not covered:

 - Tests
 - Including the package hashes of dependencies so they may match what
   is in a lock file -- they're being `undefined` instead, which may
   break some lookups. The previous format did not lend itself to hashing
   in the same way, and it is possible transitive deps were not being
   tracked properly, or worked by respecting the current package hierarchy.
   This will require further analysis

For now this commit can allow reviewing and discussion.

allow using an alternate regex to locate test modules during eunit runs

{`eunit_test_regex`, Regex}` will use the supplied `Regex` instead of
the default to locate tests in test dirs. note this matches only the
filename, not the path. the regex is applied to all test dirs, recursively

fixes #1331

compile + cover compile prior to analyzing coverdata

recompile all files when a parse transform given as an opt needs updating

there's no way to detect which files actually rely on a parse transform
passed to the compiler via the options (as opposed to `-compile(..)`
so if any parse transforms are in modules that need recompiling just
recompile the world

fixes #1328

don't compile when resetting coverdata

fixes #1327

update bbmustache 1.3.0

log error if a module failed to load_file, the user should be aware

Prevent crashing when `mv` warns and report warnings to the user instead.

In some cases, mv will throw a warning, while still moving the files
correctly and returning a 0 return code:

"mv: can't preserve ownership of ... Permission denied".

Atomically load changed erlang modules. Non-atomically load nifs. Reference to https://github.com/erlang/rebar3/pull/1317

opps. Infinite loop fixed.

https://github.com/erlang/rebar3/pull/1317 
In reference to with support to load erlang code atomically but load nifs non-atomically.

Print stacktrace in a more conventional way

Insert a newline before printing the stacktrace so that the term is
easier to read and copy. This is a more conventional way to print
traces, and is, for instance, the way it's done by make and python.

reset accumulated coverdata on writing out to disk

`cover:analyse/0` didn't exist pre-otp18

provider chains like `eunit, ct, proper` from misreporting cover
stats from providers later in the sequence

Fix crash when doing hash check with missing index

Cover excl mods

Specifically, when fetching an application where the expected hash is
unknown, the hash is validated from the hex index; when the index is
available, the hash is fetched fine and later inserted in the lock file.

However, if the index is not available, the call would simply crash.
This patch fixes thing so that instead, the index is refreshed before
giving up and failing.

- brings back former error handling and debug messages
- keeps the filtering of excluded mods and debug messages
- breaks up code into multiple functions and removes nesting

Equivalent trim_all in bin split for <17.x

The trim_all option used in binary:split/3 is not supported in 17.x.
This patch makes an equivalent operation by eliminating empty split
fragments. From the docs:

    trim
    Removes trailing empty parts of the result (as does trim in
    re:split/3.

    trim_all
    Removes all empty parts of the result.

The new expression is therefore equivalent to the old one, but with the
added benefit of compatibility.

Fixes #1275

upgrade relx to 3.21.0

Fix Edoc cross-links in umbrella projects

Given the topological sort applied to top-level apps, we should be able
to carry the edoc values for paths configured when more than one app
exists.

This allows multiple disjoint app to have defined cross-linking in the
documentation.

Tests pending.

Print error on too many help arguments

Previously the help task would crash when given more than two
arguments. After this change it instead print a message:

    Too many arguments given. Usage: rebar3 help [<namespace>] <task>

Hookable escript

Repeats some of the steps used in the bootstrap script for non-windows
systems so that 'rebar3 escriptize' can be used in development for
faster results:

- ./bootstrap  9.95s user 1.55s system 102% cpu 11.234 total
- rebar3 escriptize  0.49s user 0.14s system 101% cpu 0.623 total

This will allow to move and modify the generated files