Skip hrefs for broken remotes

I'm running 0.16.9.dev0+gb5dd092.d20201113 from Arch AUR and run into an issue with a broken CalDAV remote (SmarterMail Enterprise Build 7661). It seems to poorly handle objects when URL encoding is required, failing to open these calendar events in its own UI and they don't seem to be available in its DAV endpoint either. During sync it hits the NotFoundError exception and I've not been able to get these objects manually with different combinations of encoding.

As it currently only affects a small number of events, all invites from other people, I'd like to be able to skip them for now. I've made a small proposal change in https://github.com/hvanderheide/vdirsyncer/commit/c1d12a42f700a1853220f2ff74963fafd0f75cf9 which adds an optional setting to do just that. Is this something worth considering at all, and would this be the right way to implement this feature?

Review the proposed change in commit c1d12a42f700a1853220f2ff74963fafd0f75cf9 and trace how sync handles NotFoundError for broken CalDAV objects. Done means an optional setting allows those objects to be skipped without stopping synchronization.