(PDB-557) Add support for standard query operators and subqueries

Now environments can be queried via URI or query parameter with the
normal operations (i.e. =, ~, not, and, or etc). Subqueries for
resources and facts are also supported.
(PDB-555) Environments for /nodes & hyphenation consistency fixes

This patch adds the relevant 'last environment seen' parameters to the nodes
end-point. This updates the tests and documentation to include these
parameters.

For consistency all parameters for the nodes end-point are now using hyphens
instead of underscores as well.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #948 from senior/ticket/master/pdb-557-environment-subqueries

(PDB-557) Add support for standard query operators and subqueries
(PDB-555) Rename *-last-environment to -environment

Instead of using facts-last-environment, we're going to use
facts-environment (same for catalog & report).
Merge pull request #949 from kbarber/ticket/master/pdb-555-environments-for-nodes-endpoint

(PDB-555) Environments for /nodes & hyphenation consistency fixes