(#1741): Fix quotes in etag values

Bump cth_readable to 1.3.3

Fixes some lager warnings since config changes

Remove noisy debug message

It makes things worse than if it weren't there.
Fixes issue #1726

sort-as: force an order on multiple profiles

This reverts commit 0f7e6c31e9.

This reverts commit 4ad1db9733.

This reverts commit 3f8dd5eace.

use debug level for logs about bad package versioning

don't attempt retry of missing packages when updating index

Env for providers

rebar_package: do not return first package version for constraint with no match

Set unicode option for standard_io at entry point

fix hooks and plugins usage when cleaning build artifacts for deps

upgrade erlware commons and relx

Issue #1704: Fix alias provider argument passing

The way arguments are passed by the alias provider is not compatible
with all rebar providers/commands. Especially the release (relx)
provider does not like getting its arguments as a plain string. It
expects its arguments in a pre-parsed format as returned by
getopt:parse/2.

Other commands, e.g. eunit, seem to be fine with both ways of argument
passing. Therefore, this fix changes the alias provider argument passing
to the getopt format in general.

find_apps didn't read config files so no hooks were in the app_infos,
and now that hooks are being done rebar needs plugins to be able
to run clean plugin hooks in deps.

Corrected Erlang Solutions Download URL [skip ci]

Current URL goes to 404 page, corrected URL to avoid confusion.

Fix repeated bootstrap runs

Fix escriptize failure when ebin/ has subdirs

Although fairly irregular, the presence of a subdirectory in ebin/ while
running rebar3 escriptize would crash the run and generate a dump.

Since ebin subdirectories are generally not supported (adding a path for
an application only adds ebin/ and no subdirectories to the VM's path
set), we just silently ignore the directory altogether.

Fixes #1693

Updating the bootstrap script in #1689 made it so symlinks that already
exist return `exist` rather than ok, in line with the regular code.
However the bootstrap module wouldn't handle this case.

This fixes the problem by ensuring that `exists` is as valid as `ok`.