Clarify that quest selection screen allows reordering

[FloEdelmann]

Closes #2828.

• Rename screen from "Quest selection" to "Quest selection and priority". I avoided the word "order", as "priority" is already used in that screen and I think it's better to stick with one word for one concept.

  

• Add a drag handle at the left of each quest selection row. Dragging there is immediately possible (without long-press), dragging anywhere by long-pressing is still allowed.

  

I used the drag-vertical Material Design Icon, should I add that to authors.txt?

[westnordost]

Nice, also looks more slim than I thought! Though, regarding the size, according to the accessibility guidelines, the minimum size for a tap area should be about 40dp (ideally 48dp), see

https://material.io/design/usability/accessibility.html#layout-and-typography

If this is becoming too wide, one possibility to have it visually still small, but the invisible click area overlaps with the icon.

[westnordost]

avoided the word "order", as "priority" is already used in that screen and I think it's better to stick with one word for one concept.

👍

[FloEdelmann]

I've made the touch area bigger, so it's now 48dp wide (and still fills the available height):

[westnordost]

Nice, thanks!

[matkoniecz]

I used the drag-vertical Material Design Icon, should I add that to authors.txt?

It may be overkill, at that point such work is no longer eligible for copyright anyway. But adding would be still OK.