This is a hacky workaround to make things work until we find a better
solution.

Closes: https://todo.sr.ht/~emersion/alps/96

This causes the mailbox to automatically reload the page every 60
seconds, without JavaScript.

This also updates the base template data to include the full URL, and
replaces the earlier "Path" field with a pre-split array of path
components, which is more immediately useful to most templates given the
limitations of string munging with text/template primitives.

Don't issue a CardDAV query with any filter, Google won't return any
result.

A new minimal CardDAV plugin is introduced. It injects a list of e-mail
addresses in the e-mail compose view.

References: https://todo.sr.ht/~sircmpwn/koushin/7