* fix a bug in how email summaries are flattened across multiple
accounts, which was previous resulting in empty email objects
* allow negative offset in email pagination
* make all /emails endpoints return emails without bodies
* upgrade Stalwart image for devtools/full to 0.14.1
* re-assert which features are implemented or not in 0.14.1
* refactor the integration tests yet again to make it clearer and
easier to see those "features-or-not"
* get rid of old tests that are now better covered by integration tests
* rewrite how we compare expected and actual objects in integration
tests, finally having found a way to ignore the @type attribute
properly instead of having to mutate all objects to remove it
* add endpoints for Mailboxes:
- PATCH mailboxes/{id}
- DELETE mailboxes/{id}
- POST mailboxes
* refactor the pkg/jmap and groupware framework to systematically
return a jmap.State out-of-band of the per-method payloads, since
they are almost always present in JMAP responses, which lead to the
artificial creation of a lot of composed struct types just to also
return the State; on the downside, it adds yet another return
parameter
* made several email related operations multi-account:
QueryEmailSnippets, QueryEmails, QueryEmailsWithSnippets
* add GetIdentitiesForAllAccounts
* add GetEmailsForAllAccounts
* jmap: add CreateIdentity, UpdateIdentity; groupware: add
GetIdentityById, AddIdentity, ModifyIdentity
* add temporary workaround until Calendars, Tasks, Contacts are
implemented in Stalwart when determining the default account for
those: use the mail one in the mean time
* fix(jmap): fix bug where CommandBlobUpload was used instead of
CommandBlobGet in GetBlob (now GetBlobMetadata)
* we currently don't need a variant of BlobGetCommand that also
retrieves the content of the blob, instead we only use it for
retrieving metadata about it
* the JMAP error handling was not working properly, fixed it and added
error definitions accordingly
* add operations to retrieve mailbox roles and mailboxes by role for
all accounts
* introduce a function 'mcid' to assemble method call IDs per account
instead of doing that inline in each function, in case the rules for
doing so change in the future
