PQL & Hashes: Provide hash projection capability for facts & resource params

Improvements to make PQL easier to user/more easily understood would be a very good thing given it's the primary way to query data from the system as well to select nodes to run tasks against. This use case is likely the most common one for extracting node data. PQL is central to using Puppet/PE and usability improvements should be prioritized. Without this consultants and customers are forced to do a lot of post-processing of the full dataset to pick out the handful of fields they want as seen in Reid's example below. Common scenarios that are impacted like this are integrations with CMDBs and ticketing systems(e.g. Remedy) where customers want data grabbed regularly.

The inventory and resource endpoints now support using dot notation for projections. This will allow you to pick specific a specific fact or resource parameter to return instead of the entire json for facts or parameters. You can find examples of using dot notation in [PQL](./api/query/examples-pql.markdown) and [AST](./api/query/v4/ast.markdown) Known issue - PDB-4521