 Refactor codebase to async/await - `m365 spo eventreceiver`, `m365 spo externaluser` and `m365 spo feature` 

This issue is for the refactoring of the  `m365 spo eventreceiver`, `m365 spo externaluser` and `m365 spo feature` commands, more specifically:

- m365 spo eventreceiver get
- m365 spo eventreceiver list
- m365 spo eventreceiver remove
- m365 spo externaluser list
- m365 spo feature disable
- m365 spo feature enable
- m365 spo feature list
