query: allow attributes size, precision, scale on tag value
query: allow attributes size, precision, scale on tag value

The value tag for queries can contain more specific information
about its data type. Ideally, those data are read from the database
schema but this is not implemented yet. This leads to some duplication
of data specifications. We will use it until it is maintainable.

Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server