[iOS] Setup CI: Github Actions

[luongvo]

Why

We need a CI pipeline to automatically analyze and test all feature branches before merging.

Acceptance Criteria

• Use GitHub Actions.
• Add workflow to automatically analyze and test all feature branches before merging, which has flowing steps as below:
  • get and prepare the necessary components.
  • check formatting and analytic code.
  • execute unit and UI tests.
  • integrate Danger to automate review PR.