UI for making encrypted ssh remotes with gcrypt

Improved probing the remote server, so it gathers a list of the
capabilities it has. From that list, we can determine which types
of remotes are supported, and display an appropriate UI.

The new buttons for making gcrypt repos don't work yet, but the old buttons
for unencrypted git repo and encrypted rsync repo have been adapted to the
new data types and are working.

This commit was sponsored by David Schmitt.

Assistant/WebApp/Configurators/AWS.hs

@@ -205,7 +205,8 @@ enableAWSRemote _ _ = error "S3 not supported by this build"
 makeAWSRemote :: SpecialRemoteMaker -> RemoteType -> StandardGroup -> AWSCreds -> RemoteName -> RemoteConfig -> Handler ()
 makeAWSRemote maker remotetype defaultgroup (AWSCreds ak sk) name config = do
 	liftIO $ AWS.setCredsEnv (T.unpack ak, T.unpack sk)
-	setupCloudRemote defaultgroup $ maker hostname remotetype config
+	setupCloudRemote defaultgroup Nothing $
+		maker hostname remotetype config
   where
 	{- AWS services use the remote name as the basis for a host
 	 - name, so filter it to contain valid characters. -}