Backport of GCS refactoring

[nicholaspcr]

Summary

OS counterpart of https://github.com/TheThingsIndustries/lorawan-stack/pull/4310

Changes

• Deprecate DCS authorizeGateway and UnauthorizeGateway
• Remove authorize and unauthorize CLI sub-commands
• Update tests everywhere and improve code coverage.
• Introduce clean gateway claiming flow that only creates gateways.

Testing

Steps

For this OS PR the only tests performed are the unite tests, no manual testing yet.

Regressions

Notes for Reviewers

This is a backport of a PR done in https://github.com/TheThingsIndustries/lorawan-stack/pull/4310

I went over each file, double checking the contents but its worth having a second read by someone else.

@KrishnaIyer this backport was done by @johanstokking's request in the hopes it alleviates your workload.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.

[KrishnaIyer]

Thanks I'll pick this (for review I mean)

[KrishnaIyer]

LGTM with a few comments.

• Please also backport the observability changes for unclaiming.

[KrishnaIyer]

LGTM. Please fix CI, merge and do a merge to enterprise.