ParamInfo class

Manages data from the paraminfo which was previous managed within
QueryGenerator and stored in APISite._modules.

This provides preloading of an initial set of params, so the cache
key is constant, and bulk loading of all query params, again so that
the cache key is constant irrespective of order of queries used.

Change-Id: I84a0769f19abf8740106659426109c62e8438e65
Merge "ParamInfo class"