Delete a bunch of old images

These are only images that I was >99% sure we did not need. There
are probably still some random graphics lingering around, but I
think I got the bulk of the obviously-orphaned ones.
fix cost est. for instance, fixes: #359
Merge pull request #360 from martinpovolny/cost-rhevm2

fix cost est. for instance in some cases (rhevm)
Switch providers#edit with providers#show
Switch providers#edit with providers#show - fix tests
Delete provider toggle
Delete provider toggle - fix tests
Merge pull request #358 from n1zyy/old_images

Delete a bunch of old images
Merge pull request #366 from ifarkas/providers_refactor

Providers page refactor: switch providers#edit with providers#show