trigger lektor/translations build when translation.git/[website] updates

For the work of translators, we have a staging site so they can review their work before publishing it (see parent ticket).

When there are updates in transifex, we get them in the repository

https://gitweb.torproject.org/translation.git/ [website]

where website can be support-portal, community, etc.

We need that jenkins builds then the branch /translations/ of the website repo, so the translatos can see their work and correct any errors.

So, any changes to https://gitweb.torproject.org/translation.git/commit/?h=support-portal should trigger the build of https://gitweb.torproject.org/project/web/support.git/log/?h=translations

any changes to https://gitweb.torproject.org/translation.git/commit/?h=tbmanual-contentspot should trigger the build of https://gitweb.torproject.org/project/web/manual.git/log/?h=translations

any changes to https://gitweb.torproject.org/translation.git/commit/?h=communitytpo-contentspot should trigger the build of https://gitweb.torproject.org/project/web/community.git/log/?h=translations

https://gitweb.torproject.org/translation.git/commit/?h=tpo-web should trigger the build of https://gitweb.torproject.org/project/web/tpo.git/log/?h=translations