Comment
Rename to make purpose clearer
Implement #1122 "Use Liferay language as requested Form Runner language"

- FR
  - support Orbeon-Liferay-Language
  - "cleans" language, i.e. "en_US" becomes "en"
  - don't show language selector if Orbeon-Liferay-Language provided
- proxy portlet
  - send Orbeon-Liferay-Language if configured
  - preferences: dropdowns and checkboxes, refactor, style
  - support FR Home page
- add ExternalContextOps
- comments