Training materials should be displayed from most recent

[bianchini88]

Among the first entries, some materials from 2021/22 are displayed. More recent materials should be displayed first. The API call to TeSS should be revised.

[bianchini88]

Some of the material was published recently, and these are the dates picked up by the API... the solution is not obvious.

[bianchini88]

Tagging @ehj000, as he provided the workshops, and @Workberg as Training Coordinator. We either change the dates in the metadata or add ISO dates at the beginning of the titles (and order by title, not chronologically).