Change xref paths to only those of runtime deps

This commit adds new checks in the `set_paths` test case related to
runtime apps and their path handling with the `runtime` target in
`rebar_paths`. These new checks also hope to increase the coverage
of the changes done to the xref provider in this same PR (#2354).

This commit also adds some new helper functions to help deal with
future changes related to these new checks (i.e., changes related to
the runtime apps), besides fixing a problem when looking for the
first instace of an app/dep/plugin in the path while testing.

Add `alias` to example `rebar.config.sample`

Update README with supported Erlang/OTP versions

Fix `dialyzer` warning output for option `unknown`

... and e.g. an unknown type is detected

Add xref_ignores to sample config file

Especially for those that rely on the sample rebar.config from the get-go

This commit changes mainly the `rebar_paths` module by adding a
new `runtime` target. When using that target, `rebar_paths:get_apps/2`
will, for each project app, find all their `applications` and
`included_applicactions` and filter those that could be found
in rebar3's state.

Fix lock file not being generated when no deps are present in the config

Prevent crash when function deemed undefined has no local context

use 'aws cp' when copying escript to s3

Bump 3.14.1

git lock: abort if version is not equal to or greater than 1.8.5

require the app name as the last part of git_subdir path

Fix Recursive Behaviour Lookup Regression

This was due to a subtle mistake in the new code in
https://github.com/erlang/rebar3/pull/2322 which optimized the search
behaviour of files not found by EPP. The patch mistakenly always kept
the top-level src/ directory for an app even if it did a lookup in
recursive ones.

This patch tracks and maintains the proper subdirectory hierarchy. To
keep performance adequate, the lists:keyfind/3 function is used, which
is also now a NIF to the same extent as lists:member/2; manual lookups
would likely end up reducing performance, particularly in deep
hierarchies.

A test case has been added to track the regression.
Reported by @elbrujohalcon

bump version to 3.14.0

Remove erl_interface from makefile template

upgrade relx to 4.0.0

upgrades relx which now checks for undefined functions of project apps

Improve warnings about checkout dependencies when locking and upgrading

fixes https://github.com/erlang/rebar3/issues/2323

Add missing credits

bump dependencies prior to next release

Extract rebar3 libs in a version dependent directory when using local commands