chore: Workflow documentation (#1825)

* Refactor: Migrate to fastlane for android & ios firebase app distribution

This commit migrates the Android and iOS Firebase app distribution process to use Fastlane.

- Removed the custom Gradle task for Firebase app distribution.
- Removed the firebase appdistribution plugin from the project.
- Implemented `android deploy_on_firebase` Fastlane lane for Android Firebase app distribution.
- Implemented `ios deploy_on_firebase` Fastlane lane for iOS Firebase app distribution.
- Updated the internal release workflow to trigger the Fastlane lanes.
- Updated documentation to reflect the changes.
- Updated the weekly schedule workflow to trigger the new workflow for internal release.

* Added Documentation & Comments

Author: niyajali