Increase the quality of translations. Cleanup legacy translations.

We had an interesting conversation in the Core Team Call about the Sakai
Translations.

About 8 months ago I did a research about the status of the Sakai
Translations, looked for the contacts and contributors of each language,
sent emails to more than 40 people, surfed Confluence looking for
information of the translations....got a small number responses from the
community. I summarized the status here [1], based on the numbers of
Transifex, the translation system that the community uses nowadays [2].

We announce in our website [3] that "Complete or majority-complete
translations of Sakai are available in more than 20 languages.", that's a
good marketing argument but, in my opinion, some of the translations come
from the 2000s and are completely dated and are not supported anymore.

My proposal is moving these legacy translations [4] to Sakai Contrib as
"Language Packs" and removing them from the Sakai 19 source, with the
main goal of having healthy supported translations.

[1] https://github.com/sakaiproject/sakai-reference/blob/master/docs/readme_l10n.md

[2] [ https://www.transifex.com/apereo/sakai-trunk/|https://www.transifex.com/apereo/sakai-trunk/]

[3]https://www.sakaiproject.org/languages

[4] All the translations declared as "Unverified" except probably the
fr_FR.