* Put new 12.0 version and remove old 10 version not supported
    anymore.

  * Missing update of docker-compose so that the build don't put back
    12.1-alpine

[Misc] Upgrade to latest 12.x version of PostgreSQL to reduce maintenance but also to match the JDBC driver used in the XWiki docker image.

[Misc] Upgrade to latest 12.x version of PostgreSQL to reduce maintenance but also to match the JDBC driver used in the XWiki docker image.

* Commit missing files

* Also update the compose files

* Typo

In order to use secrets for mysql root password the parameter needs to MYSQL_ROOT_PASSWORD_FILE

Fix broken link

* And switch to AdoptOpenJDK 8.x for XWiki 10.x (since XWiki 10.x doesn't support Java 11)

[Misc] Remove dead code since we don't release Docker images on XWiki 9.x anymore (LTS has moved to 10.x)

* Typo2

* Typo

* Improved a bit the PR from Ashish