AC26: Add ability to arbitrarily arrange folders in Layers panel

[Professor Pickle]

Folders in the layers panel are awesome but please let us arrange them in any order we want. We are still slaves to alphanumeric ordering, which is not all that great.

[DGSketcher]

I love alphanumeric ordering, it appeals to the dominant logical part of my brain, assuming it is consistent in its implementation 🤓

[Professor Pickle]

Alphanumeric is a good default. However, I need the flexibility to group and arrange according  to a particular logic that changes over time or between specialised templates. .