SSO domain verification for multiple domains

Most SaaS platforms I'm aware of do domain ownership verification via the addition of TXT records in DNS. Logi Sync should follow suite

Currently, it's convoluted and message process to get extra domains added for SSO enablement:
- Most provision a user with new domain
- Have the user accept invite and sign-in (or send the invite to the Sync owner/admin)
- Assign owner role to the user (which may not be appropriate for the user) and beging domain verification