* refactor the jmap package to split it into several files as the
jmap.api.go file was becoming too unwieldy
* refactor the Groupware handler function response to be a Response
object, to be more future-proof and avoid adding more and more
return parameters while handling "no content" response as well
* more godoc for the JMAP model
* add Email creation, updating, deleting (Email/set,
EmailSubmission/set)
* add endpoints
- POST /accounts/{accountid}/messages
- PATCH|PUT /accounts/{accountid}/messages/{messageid}
- DELETE /accounts/{accountid}/messages/{messageid}
* 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...
