Refactor codebase to async/await - `m365 spo file add` until `m365 spo file retentionlabel ensure`

This issue is for the refactoring of the  `m365 spo file add` until `m365 spo file retentionlabel ensure` commands, more specifically:

- m365 spo file add
- m365 spo file checkin
- m365 spo file checkout
- m365 spo file copy
- m365 spo file get
- m365 spo file list
- m365 spo file remove
- m365 spo file rename
- m365 spo file retentionlabel ensure