Enable lang selection without need for 'available-langs.properties'

Created by: awoods

Related PRs:

• https://github.com/vivo-project/VIVO-languages/pull/57
• https://github.com/vivo-project/Vitro-languages/pull/24
• https://github.com/vivo-project/Vitro/pull/169

Resolves: https://jira.lyrasis.org/browse/VIVO-1848

Interested parties

@VIVO-project/vivo-committers