Add a reload wallpapers button (tray menu) #1822

[Ju1-js]

Initial Problem

When I was developing html wallpapers for lively awhile back, I found that I had no easy way to reload/refresh the wallpapers without the app open.

Proposed solution

Adds a "reload wallpapers" button to the tray menu, only in english for now, other languages will have to be translated.

Alternatives

I used to just leave the app open and right click -> set as wallpaper to reload it like: #1689

Ps. I came back to this though when I was looking through issues and found #1822

[CLAassistant]

All committers have signed the CLA.

[rocksdanister]

I don't feel there is a need for separate UI since SetWallpaper command to reload:
https://github.com/rocksdanister/lively/wiki/Command-Line-Controls#set-wallpaper

Also ResetWallpaper shutsdown everything and restarts, its not meant to be used to reload wallpaper.

[Ju1-js]

I don't feel there is a need for separate UI since SetWallpaper command to reload: rocksdanister/lively/wiki/Command-Line-Controls#set-wallpaper

Also ResetWallpaper shutsdown everything and restarts, its not meant to be used to reload wallpaper.

New commit essentially duplicates desktopCore.ResetWallpaper, but doesn't terminate everything.

I'll also look into simply firing a command at lively on save in terms of the workflow, but I think I could be nice to have a dedicated button for reloading things.

[Ju1-js]

You're probably right in assuming that most wallpapers aren't going to need to be reloaded, it would mostly be html based ones.
However I feel it could be nice for anyone wanting to restore their html wallpaper to it's original state without opening the ui.

[rocksdanister]

Similar to random just added a reload wallpaper command for setwp to make it easy 41af1d7

Along with future hotkey support which will let users register custom lively commandline commands directly: #665

I feel this is better and more versatile than adding too many options in the interface, therefore I am closing this.