Added setup instructions for Dovecot oauth2 support

modoboa_installer/scripts/files/dovecot/conf.d/10-auth.conf

@@ -96,7 +96,7 @@ auth_master_user_separator = *
 #   plain login digest-md5 cram-md5 ntlm rpa apop anonymous gssapi otp skey
 #   gss-spnego
 # NOTE: See also disable_plaintext_auth setting.
-auth_mechanisms = plain login
+auth_mechanisms = plain login oauthbearer xoauth2
 
 ##
 ## Password and user databases
@@ -120,6 +120,7 @@ auth_mechanisms = plain login
 
 #!include auth-system.conf.ext
 !include auth-sql.conf.ext
+!include auth-oauth2.conf.ext
 #!include auth-ldap.conf.ext
 #!include auth-passwdfile.conf.ext
 #!include auth-checkpassword.conf.ext

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

@@ -0,0 +1,5 @@
+passdb {
+  driver = oauth2
+  mechanisms = xoauth2 oauthbearer
+  args = /etc/dovecot/conf.d/dovecot-oauth2.conf.ext
+}

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

@@ -0,0 +1,6 @@
+introspection_mode = post
+introspection_url = %{oauth2_introspection_url}
+username_attribute = username
+tls_ca_cert_file = /etc/ssl/certs/ca-certificates.crt
+active_attribute = active
+active_value = true