* implement ContactCard retrieval endpoint for syncing
* re-implement that endpoint for Email too
* fix the Mailbox changes endpoint to actually return changes about
Mailboxes, and not about Emails
* when querying the diff of Mailboxes without any prior state, return
an error since the result is not what one would expect
* introduce the 'changes' API tag and group
* refactor the successful response functions to consistently return an
object type and object state whenever possible
* move the syncing endpoints under /accounts/*/changes/ for better
clarity, e.g. /changes/emails instead of /emails/mailbox/*/changes
- fix a bunch of minor issues and typos that were found using GoLand
and gosec
- add a gosec Makefile target for Groupware related files, in
services/groupware/Makefile
- enable checking JMAP session capabilities for events and contacts,
and only enable skipping that check for tasks until those are
implemented in Stalwart as well
- fix a CWE-190 (integer overflow or wraparound) found by gosec
- consistently use struct references for methods of Groupware and
Request, instead of mixing up references and copies
- always log errors when unable to register a Prometheus metric
