Add ability to drag-n-drop sort tasks

[NobleKangaroo]

The website is very flexible, and this is good. So many things can be manually sorted and persist.

For instance,

Mods - sortable

Support tiers - bang on

Shop packs - good to go!

But not tasks

You can sort them using the table header sort options, but this isn't very flexible (doesn't allow you to specify an exact order, only sorting by simple alphabetical criteria), does not persist between login sessions, and does not stay sorted for other admins in a multi-admin system.

I would love to see this ability, as it would make finding what you're looking for a lot easier if you have lots of tasks.

Thank you!