connector/microsoft implements authorization strategy via Microsoft's
OAuth2 endpoint + Graph API. It allows to choose what kind of tenants
are allowed to authenticate in Dex via Microsoft:
* common - both personal and business/school accounts
* organizations - only business/school accounts
* consumers - only personal accounts
* <tenant uuid> - only account of specific tenant
Signed-off-by: Pavel Borzenkov <pavel.borzenkov@gmail.com>
