[geary] (19 commits) ...Merge branch 'wip/714876-goa-oauth2-support' into 'master'

[Michael Gratton <mjog src gnome org>]

Summary of changes:

  677b1ce... Rename ServiceInformation.service to protocol to reduce red (*)
  ee1dcb5... Move Endpoint prop from account to service info. (*)
  70114b1... Fix intermittent error obtaining shared endpoint references (*)
  ecf25a2... Update CredentialsMediator API. (*)
  863a11e... Rename Geary.Service to Protocol, move into ServiceInformat (*)
  054d53a... Move CredentalsMethod enum and property to Credentals. (*)
  acac68a... Make ServiceInformation.mediator a required, read-only prop (*)
  a165d96... Ensure SMTP credentials are null when both noauth and use_i (*)
  13c92c3... Convert Credentials and CredentialsMediator to refer to tok (*)
  2973138... Add OAUTH2 to Geary.Credentials.Method. (*)
  b8b1482... Add support for OAuth2 GOA accounts. (*)
  ada7f3f... Add support for (X)OAuth2 SMTP authentication. (*)
  865f23b... Add support for (X)OAuth2 IMAP authentication. (*)
  b95cb08... Ensure GMail and Outlook GOA accounts are marked as such wh (*)
  538809c... Rework GOA account management to allow tracking disabled ac (*)
  f3d5430... Ensure disabled accounts show up in the dialog list. (*)
  94fb1ec... Clean up some issues with SSO accounts in the accounts dial (*)
  4f07a5d... Minor code cleanup. (*)
  5e45956... Merge branch 'wip/714876-goa-oauth2-support' into 'master'

(*) This commit already existed in another branch; no separate mail sent