Stub query2 call integration into QueryD

This patch corrects the definitions in Qlang.hs to match what Python
expects on the wire; this means replacing some manual data type
definitions with 'buildObject' so that we get serialisation (and field
names) for free, adding (manually) JSON instances for types which are
not represented as objects in JSON, etc. Due to more TH usage, I had
to shift some definitions around, since TH breaks the "define in any
order" property (☹️

).

After that, we simply add a call into the stub Query/Query.hs module
which, for all queries, responds with "query not supported". The
reason for the deep directory structure is because I want to separate
the functionality into multiple submodules, for smaller module size
and readability.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Agata Murawska <agatamurawska@google.com>