Summary:
Implement par of the discussion https://github.com/react-native-community/discussions-and-proposals/discussions/411, except the `.nvmrc` part, this includes:
- Setting `.ruby-version` in the main project and also `template/`
- Fixing the CocoaPods version with a project-level `Gemfile` and also `template/Gemfile`
- Using all `pod` executions from `bundle exec pod`, using the determined version
- Script to manage and update the ruby version
## Changelog
[iOS] [Added] - Gemfile with CocoaPods 1.11 and ruby-version (2.7.4)
Pull Request resolved: https://github.com/facebook/react-native/pull/32303
Test Plan: Build for iOS and run all CircleCI tests to see if nothing changed
Reviewed By: RSNara
Differential Revision: D31344686
Pulled By: fkgozali
fbshipit-source-id: 25c63131ca9b16d3cf6341019548e0d63bdcaefe
