* 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
* 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
* add more documentation for properties
* fixes after a bit of trial-and-error with go-swagger
* fix email filter marshalling when there are no search criteria
* introduce an apidoc.yml that contains Swagger data and is merged when
generating the swagger.yml from sources
* ensure that all the jmap responses contain the SessionState
* implement missing errors that were marked as TODO
* moved common functions from pkg/jmap and pkg/services/groupware to
pkg/log and pkg/structs to commonalize them across both source trees
* implement error handling for SetError occurences
* Email: replace anonymous map[string]bool for mailbox rights with a
MailboxRights struct, as the keys are well-defined, which allows for
properly documenting them
* introduce ObjectType as an "enum"
* fix JSON marshalling and unmarshalling of EmailBodyStructure
* move the swagger documentation structs from groupware_api.go to
groupware_docs.go
* fix: change verb for /groupware/accounts/*/vacation from POST to PUT
* refactored the models to be strongly typed with structs and mapstruct
to decompose the dynamic parts of the JMAP payloads
* externalized large JSON strings for tests into .json files under
testdata/
* added a couple of fantasy Graph groupware APIs to explore further
options
* added k6 scripts to test those graph/me/messages APIs, with a setup
program to set up users in LDAP, fill their IMAP inbox, activate them
in Stalwart, cleaning things up, etc...
