Ease debugging, fix some CI issues, tweak folder structure (#200)

* Enable debug for OTP versions' listings

* Make it easier to detect

* Prevent error annotation on expected error

The fact that one mirror fails in the above test and others follow
working is test enough for me

A single failing mirror should fail, but it's confusing to have
an error annotation for a success (via continue-on-error) while
not being able to suppress it via GitHub Actions

* Trying to figure out why we have a rebar_core exception

Might simply be that the bug is already fixed and we need to bump rebar3

* Try to debug into non-JSON input

* Prevent error in rebar_core

We're getting Access Denied for
Fetching registry from "https://repo.hex.pm:443/registry.ets.gz?"

* Try to figure out what's breaking tests

* Make jsonParse(...).map failure more understandable

* Ease test maintenance

* Tweak folder structure while moving console._ to core._

test/projects/elixir_mix/.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]