Add weblate.org to our appcivist-docker compose

[cdparra]

Issue Description

Translations issues are managed by a spreadsheet (https://docs.google.com/spreadsheets/d/1dF5qllbwNL8l7KqMsQkDDpx73vQhOX3cU-L4zSkPRwo/edit?usp=drive_web)
And it's not scalable and it does not allow us to easily translate other components other than the UI

Solution

• Made a research about how to install weblate
• Install weblate in testing server XSEDE 149.165.156.149
  Ref1: https://weblate.org/en/
  Ref2: https://docs.weblate.org/en/latest/admin/deployments.html#docker
  Make sure to run weblate in a port different than 80
• After weblate was testing, modify the docker compose file to include our weblate server.
• Update production server XSEDE 149.165.156.246 using the docker compose update between 8 an 8:30 am Asuncion time.
• Document how to create translation projects:
  1. In appcivist-pb-client, we need to translate json files (check with @gvescu)
  2. In appcivist-platform, we need to translate text files for play-framework

[yolile]

@cdparra weblate available for testing at http://149.165.156.149:7000/