engine,userportal,webadmin: configurable unsupported locales

- Added UnsupportedDisplayedLocales configuration variable to
  control which unsupported locales are displayed. Any locales
  in this list which are also in the UnsupportedLocaleFilter list
  will still be displayed.
- Added UnsupportedLocalesFilter configuration variable to control
  which locales are unsupported. Any locale in this list will NOT
  be displayed unless they are also in the UnsupportedDisplayedLocales
  list.
- Modified pom files to use the languages.properties as the source file
  of which locales are available, instead of being hardcoded in the pom
  file itself.

Change-Id: I5b816694d6c34549360b189eb85c840688957bdb
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1096525
Signed-off-by: Alexander Wels <awels@redhat.com>