Remove all deprecated actions + Related code

[mokagio]

What does it do?

They became obsolete with the introduction of the Versioning module in d050d84 (#512) and as discussed in #579 (review) we ought to move forward in deleting them and ship a new major version.

Internal ref paaHJt-6gp-p2

Checklist before requesting a review

• Run bundle exec rubocop to test for code style violations and recommendations
• Add Unit Tests (aka specs/*_spec.rb) if applicable
• Run bundle exec rspec to run the whole test suite and ensure all your tests pass
• Make sure you added an entry in the CHANGELOG.md file to describe your changes under the appropriate existing ### subsection of the existing ## Trunk section.
• If applicable, add an entry in the MIGRATION.md file to describe how the changes will affect the migration from the previous major version and what the clients will need to change and consider.

[dangermattic]

	1 Warning
⚠️	This PR is larger than 500 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

Generated by 🚫 Danger

[AliSoftware]

Overall LGTM, but I'd love to have @spencertransier chime in and give the final PR review/approval especially wrt the removal of the lib/fastlane/plugin/wpmreleasetoolkit/helper/android/android_version_helper.rb file, to confirm it's really not used anywhere in the release-toolkit codebase itself (e.g. by the Versioning module calling into it—I doubt it but better safe and double-check than sorry) or if it's used by any of our client repos, making sure that all the methods in here have a counterpart in the Versioning module they can be replaced with (I think they do, but again, better safe than sorry).

[mokagio]

I've been using this branch in Automattic/simplenote-android#1676 and so far so good 😄

[spencertransier]

@mokagio Sorry I missed this! I will review it this week.

[spencertransier]

Was this intended to be require_relative instead of return_value?

[spencertransier]

I went through and verified that all the removed methods are not used anywhere but in Simplenote Android/iOS/Mac, which I know you're already working on updating. I just had a question about a require_relative vs return_value. Besides that, everything looks great. Approving to unblock.