Clean-up branding directories
During work on legacy/trac#25702 (moved) we realized that the branding directories contain old cruft which is not needed anymore (like the .bmp file changes). We should go over our branding patch(es) and make sure we have everything we need (and only that).
The first branding patch is the one for legacy/trac#2716 (moved). It could be worth merging the one from legacy/trac#25702 (moved) with it and doing the clean-up while that happens (i.e. during the esr68 rebase). Putting it tentatively on that radar.