rm HMWF partner template
generic partner-branded base template and mods to tmplt chooser

- ui.choose_base_template can now return a generic partner
  template (e.g. ui/base-partner.html) in addition to the master
  and partner-specific templates.
back-end changes to partner-branded site functions

- Use settings.PARTNER_DOMAINS instead of ORG_DOMAINS for
  terminological consistency.
- ui.domain_org returns tuple (repo,org) instead of just org
- Helper function for filtering views by partner if partner is
  present.
more appropriate display for partner-branded collections-list

No list of other orgs when showing a specific partner's objects.