New command: Restore deleted Office 365 group #346

Only supported in the Beta Graph endpoint as of today, but I recon it would look like this:

Restore the specified deleted Office 365 group,

• command: graph o365group restore -i|--id <id>
• id: the ID of the Office 365 group to restore
• requires connection to the Microsoft Graph (Add support for authenticating to MS Graph #10)