Maintenance & fixes (#964)

## Description

### Maintenance
- Remove Firebase files to avoid crash reports from forks and update
Android and iOS Firebase app ID
- Fix Android crash due to missing crashlytics plugin
- Regenerate `android/app/src/main/AndroidManifest.xml`
- Update `android/crane/build.gradle`
- Update releasing instructions
- Remove Fastlane production lane for deploying directly to production
(use `beta` and `promote_to_production` instead)
- Regenerate Fastlane documentation
- Remove macOS from Firebase config
- Update `Runner.xcodeproj/project.pbxproj` and `pubspec` files

### Fixes
- Disable deferred components
(#926)
- Respect brightness of web for the background
- Adjust the logo transform animation on web
- Fix Android splash screen `backgroundColor` (Fixes
#930)

---

>**Note**: Please find the development and releasing instructions at
https://github.com/flutter/gallery#development

Prepare 2.9.2 release (#513)

Use package_info_plus (#511)

Prepare 2.9.0 release (#491)

Make drawer shade and mailbox title fade to be in sync with drawer an…

…imation (#310)

Update README.md (#232)

Fix error in command

Update mac screenshots (#165)

Former-commit-id: b0e3ae8

[Gallery] Bump version to 2.3 (#321)

Former-commit-id: 7e26897

Bump version to 2.2 (#247)

Former-commit-id: e1c7a14

Bump gallery to v2.1 (#208)

Former-commit-id: 5971c65