[Feature Request] Configurable wallpaper storage location

[ifl0w]

I've tried to write a package for Gentoo for this extension and stumbled across the issue that wallpapers are stored inside the extension directory. This makes it hard to write a useful package at all. I am not a fan of the http server idea or any docker image like others suggested here. On Gentoo people write Ebuilds for Gnome extensions and put extensions to /usr/share/gnome-shell/extensions which is not a good place to save the wallpapers to. Actually, this is not just a Gentoo thing as there are packages for Gnome extensions on Arch and other Distributions as well. Some people just prefer using a package manager over any random download tool or cloning git repos.

Without an option to select a custom wallpaper directory, this extension will not really work using any package manager. I've never written any extension for Gnome but would it be possible to have an option where you could select a directory instead of hard coding it with Self.path + '/wallpapers/'; in wallpaperController.js?

Originally posted by @r7l in #30 (comment)

[ifl0w]

Things improved with PR #97. So creating packages for distributions should no longer be a problem.
However, a user interface for configuring the location would be an additional improvement.

I'll leave this issue open for tracking the possible UI improvement.