Implement sync testflight config command

[DechengMa]

Implement Sync TestFlight Configuration Command for syncing local and server TestFlight configs.

Support:

• [x] Create Group
• [x] Delete Group
• [x] Modify Group
• [x] Add Testers to App
• [x] Add Testers to Group
• [x] Remove Testers from App
• [x] Remove Testers from Group

📝 Summary of Changes

Changes proposed in this pull request:

• Create TestFlightConfigLoader and TestFlightConfiguration
• Create BetaGroup and BetaTester in new FileSystem module
• Create SyncResourceComparator for comparing local and server resources
• Implement push and pull command.

⚠️ Items of Note

Due to the number of API calls, the pull config from server command will take a considerable amount of time.

Limitations:

• Can't perform creating a group and adding testers to the group at the same time.

🧐🗒 Reviewer Notes

💁 Example

Usage: asc testflight sync pull [--output-path <output-path>] asc testflight sync push [--input-path <input-path>] [--dry-run] [--refresh-local]

🔨 How To Test

swift run asc testflight sync pull swift run asc testflight sync push --dry-run swift run asc testflight sync push

[orj]

Regarding the speed of the process, is there any way we could use the ASC API's ability to include sub-resources in requests to create/update? See the WWDC20 video https://developer.apple.com/videos/play/wwdc2020/10004/ from about the 9 minute mark.