Fixes #5664 - Host filters can use taxonomies

Also disables taxonomy filters on resources that do not support them.

fixes #812 - new permissions model, user group role and nest support, role filters for better granularity

• Daniel Lobato <elobatocs@gmail.com>
• Joseph Magen <jmagen@redhat.com>
• Tom McKay <thomasmckay@redhat.com>
• Greg Sutcliffe <gsutclif@redhat.com>...