Investigate migration to Github Actions

[Clstroud]

Attempt to migrate the current CircleCI pipeline to Github Actions.

Our localization workflow is no longer working due to branch protections on develop, which we don't want to remove. Github Actions should theoretically allow us to enforce localization exports such that they occur on PR branches exclusively, while also enforcing that step as a merge requirement.

[peterkos]

Goals:

• Locally run w/ act (for devvin')
• Get output closer to the current CircleCI output (specific test success vs. hunting around in the test step log)
• Enforce localization exports on PRs (merge requirement)
• Commit an updated .xliff l11n file

@Clstroud Is there anything I'm missing? Do we want to map over the other fastlane lanes as well (ex. buildanddeploytotestflight)?