Feature/warnings quiet

[memsharded]

Changelog: Feature: Introduce new core:skip_warns configuration to be able to silence some warnings in the output.
Docs: conan-io/docs#3215

Close #13517

[AbrilRBS]

I only have one UX question:
I'm wondering if we're going to reuse some "id"s in the future, seeing how general the proposed deprecated one is. If so, maybe it's not warn_id but warn_category/warn_tag or the likes?

[memsharded]

I'm wondering if we're going to reuse some "id"s in the future, seeing how general the proposed deprecated one is. If so, maybe it's not warn_id but warn_category/warn_tag or the likes?

I initially implemented some kind of abstract ID, like W01, but then I realized that it was only adding an unnecessary abstraction, and too much boilerplate in code, translating codes back an forth. So I'd prefer to have something with a bit of semantics. We can discuss if we want Wdeprecation, Wdeprecated2.0, c3i_removed, or any other, but I'd suggest using plain text identifiers with a bit of meaning.