WIP: dovecot 2.4 support

modoboa_installer/scripts/files/dovecot/2.4/conf.d/auth-oauth2.conf.ext.tpl

@@ -0,0 +1,24 @@
+auth_mechanisms {
+  xoauth2 = yes
+  oauthbearer = yes
+}
+
+oauth2 {
+  introspection_mode = post
+  introspection_url = %{oauth2_introspection_url}
+  #force_introspection = yes
+  username_attribute = username
+}
+
+# with local validation
+#oauth2 {
+#  introspection_mode = local
+#  username_attribute = email
+#  oauth2_local_validation {
+#    dict fs {
+#      fs posix {
+#        prefix = /etc/dovecot/oauth2-keys/
+#      }
+#    }
+#  }
+#}