include/hw/qdev-core: fixup kerneldoc annotations

Fix up the kerneldoc markup and start documenting the various fields
in QDEV related structures. This involved:

 - moving overall description to a DOC: comment at top
 - fixing various markup issues for types and structures
 - adding missing Return: statements
 - adding some typedefs to hide QLIST macros in headers

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-25-alex.bennee@linaro.org>