[Tiki-devel] Plugin Convene Revamp

Hi all, look! I done a merge request! :)

    https://gitlab.com/tikiwiki/tiki/-/merge_requests/775

I've been meaning to rebuild the convene plugin for many years and finally have done it. It will require quite a bit of testing (on the dogfood servers when they're updated (mainly https://next.tiki.org i expect) and i will fix any issue quicky-quick, so let me know if you find anything disappointing.

At the moment it's more or less as it was cosmetically, and it will use the new storage format when any changes are made, so please test test test!

TIA

jonny