Update calendar-ui package, add localization settinsg if calendar plugin isn't installed

[liamcain]

My very basic/dumb approach to localization here is:

if the calendar plugin is installed, use those settings. If not, show localization settings within slated.

It's far from optimal but it is at least functional. Open to ideas for a better approach!

[tgrosinger]

Ah shoot, yeah the rrule package is a mess right now. I am using a branch from a fork because it has a required bug fix that the maintainer has not yet merged in. Let me see if I can have npm use that forks commit hash instead of the NPM published version.

[tgrosinger]

If you rebase this on the main branch it should become mergable. I don't seem to be able to do that myself.

[tgrosinger]

Thank you!