* Clean up oauth2 providers Signed-off-by: Andrew Thornton <art27@cantab.net> * Add AzureAD, AzureADv2, MicrosoftOnline OAuth2 providers Signed-off-by: Andrew Thornton <art27@cantab.net> * Apply suggestions from code review * remove unused Scopes Signed-off-by: Andrew Thornton <art27@cantab.net> Co-authored-by: techknowlogick <techknowlogick@gitea.io>