Add basic RSS feed functionality

README.org

@@ -12,6 +12,7 @@ Rename =variables-template.py= to =variables.py= and edit:
 - =orgpath=: absolute path to the root directory in which =.org= files are stored, including trailing slash
 - =localpath=: absolute path to this directory, including trailing slash
 - =serverpath=: path to directory on the server where files will be uploaded, including trailing slash
+- =domain=: =https://yourdomain.tld= without trailing slash
 - =rclonesiteroot=: path =rclone= uses to access your webserver
 - =description=: content for the “about” section (can include HTML tags)
 - =hue=: theme colour expressed as a hue from 0 to 360