* in the JMAP API as well as in several places in the Groupware
framework, use a single jmap.Response[T] object to return the
payload, the language, the session state and the etag/state instead
of individual multi-valued return values
* the "position" attribute is always set to 0 when using an anchor for
pagination, but it does not accurately reflect the position and thus
we decided to remove the attribute from the resulting object for
clarity
* omit "canCalculateChanges" attribute when its value is "true", which
is going to be the case in 100% of calls against Stalwart
* add Groupware APIs for creating and deleting addressbooks
* add Groupware APIs for creating and deleting calendars
* add JMAP APIs for creating and deleting addressbooks, calendars
* add JMAP APIs to retrieve Principals
* fix API tagging
* move addressbook JMAP APIs into its own file
* move addressbook Groupware APIs into its own file
* add example generator infrastructure, with some examples for pkg/jmap
and pkg/groupware, with more needing to be done
* alter the apidoc Makefile to stop using go-swagger but, instead, use
the openapi.yml file that must be dropped into that directory using
groupware-apidocs (will improve the integration there later)
* add Makefile target to generate examples
* bump redocly from 2.4.0 to 2.14.5
* introduce Request.PathParam() and .PathParamDoc() to improve API
documentation, as well as future-proofing
* improve X-Request-ID and Trace-Id header handling in the middleware
by logging it safely when an error occurs in the middleware
* refactor some pkg/jmap and groupware methods to make more sense from
an API point-of-view
* add path parameter documentation, but automate it by injecting their
definition into the OpenAPI YAML tree that is extracted from the
source code using go-swagger as it is too cumbersome, repetitive and
error-prine to document them in the source code; wrote a TypeScript
file apidoc-process.ts to do so
* add generating an offline HTML file for the OpenAPI documentation
using redocly, and injecting a favicon into the resulting HTML; wrote
a TypeScript file apidoc-postprocess-html.ts to do so
