chore: Automate Releases

[duncanista]

What does this PR do?

Adds GitLab pipeline and migrates current GitHub actions there.

Migrates:

• Unit Tests
• Integration Tests
• Check Layer Size
• Linting

Adds:

• Build Layer
• Sign Layer
• Publish Layer (sandbox and prod)

Motivation

Automate Layer Releases. SVLS-4265

Testing Guidelines

• [x] All test working as normal
• [x] Layers are deployed to both sandbox and prod

Additional Notes

• Removed signing for sandbox layers (shown in this PRs picture)
• GovCloud is still done manually.

Types of Changes

• [ ] Bug fix
• [ ] New feature
• [ ] Breaking change
• [x] Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• [ ] This PR's description is comprehensive
• [ ] This PR contains breaking changes that are documented in the description
• [ ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [ ] This PR impacts documentation, and it has been updated (or a ticket has been logged)
• [ ] This PR's changes are covered by the automated tests
• [ ] This PR collects user input/sensitive content into Datadog
• [ ] This PR passes the integration tests (ask a Datadog member to run the tests)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (afc1a75) 82.11% compared to head (0b569de) 82.11%.

:exclamation: Current head 0b569de differs from pull request most recent head 864e3f5. Consider uploading reports for the commit 864e3f5 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #450 +/- ## ======================================= Coverage 82.11% 82.11% ======================================= Files 54 54 Lines 2186 2186 Branches 509 509 ======================================= Hits 1795 1795 Misses 329 329 Partials 62 62 ```

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