Added result properties to action=paraminfo

Added information about the properties of the results of API calls
to action=paraminfo, including information about "property groups":
what should the prop parameter be set to to get that property.

Uses the same format for types as parameters already do.
The output format of some modules doesn't fit this, so the result
properties for them weren't added, or only partially.

Partially implemented modules:
* expandtemplates:
  parsetree is in its own tag
* protect, allusers, backlinks, deletedrevs, info, imageinfo,
  logevents, querypage, recentchanges, revisions, searchinfo,
  usercontribs, userinfo, users, watchlist, upload:
  response with partially complex structure

Not implemented modules:
* feedcontributions, feedwatchlist, opensearch, rds:
  non-standard reponse
* help:
  error is normal response; not very useful for automated tools anyway
* paraminfo, parse, pageprops, siteinfo, userrights:
  response with complex structure

Change-Id: Iff2a9bef79f994e73eef3062b4dd5461bff968ab