Add (back) image search in background image dialog

[bentsai]

It was nice being able to quickly search for a random image to use as background for spaces. Perhaps the quality of images wasn’t great, but sometimes something specific is better than the built-in ones.

also, there was opportunity for serendipitously finding a good one, even if it was ironic.

[pirijan]

thanks will do!

[pirijan]

Note to self: investigate switch from bing to https://www.pexels.com/api/ bc Microsoft 10x increased their service cost

[pirijan]

this will ship tomorrow