Add a way to update custom packs

[Shadowclysm]

It is very difficult to make changes to custom packs. There should be a button on each custom pack to load its name and tile info into the existing new custom pack text fields and give "Add Pack" button a confirmation dialog to override the existing custom pack with the same name.

[TrevorMDev]

If this were to be implemented, I would do it with a pop up that contains the pack text and let it be saved from there.

I plan to add an export functionality for all packs, which should make this easier to deal with also.

[Shadowclysm]

I see this was added recently 👍