fixes #2042 - fix CSS classes added to filter levels

scope templates by taxonomy.

Fixes #2000 - display the alternate taxonomy when editing a location or org

host routes api changes squashed

fix trend labels for ForemanTrends

fixes #1937 - Foreman doesn't work well when run on subpath

• request_url is not enough to pass form controller to tftp
  Other variables (like script_name) need to be used from
  controller.url_options to properly generate the path in the PXE template.
• use rails helper to get the path to noVNC source...

SQL improvments for paramaters in host edit section refs #2003

replaced default taxonomy migration with a multiple actions for assigning hosts to orgs and locations.

filtered users include admins, except in taxonomy form where it is no longer relevant to select admin users.

admins can always reset the taxonomy filters to any