Remove Semantic Tasks extension

[yaronkoren]

I'm not sure what's going on with this extension. Canasta until now has been using the Wikiteq fork of this extension, at https://github.com/WikiTeq/SemanticTasks, but it became unmaintained, and was just archived a few weeks ago. The official Semantic Tasks repository is at https://github.com/SemanticMediaWiki/SemanticTasks, but it too seems to be essentially unmaintained - the last non-i18n commit was over two years ago. I have no idea if Semantic Tasks works with MW 1.43, but I'm pretty sure it doesn't work yet with the current SMW version, 4.2: this discussion stated that ST was not yet working with SMW 4.x in September 2022 - and that commit I linked to is the only commit that ST has had since that discussion.

I think this extension should be removed from Canasta. It doesn't seem to get much usage: the talk page about it is minimal, and Canasta is the only package or wiki farm that uses it. It was only added to Canasta last year, in #258. As I wrote during that discussion, it's a silly use of SMW, and would have been much better implemented via a simple parser function that takes in a due date, a set of assignees, etc. But this is all sort of irrelevant if the extension isn't working in the first place

[yaronkoren]

@vedmaka - I am especially curious about your opinion on this, since you had asked for Semantic Tasks to be added in the first place.