* downgrade rubocop 0.48.1 => 0.46.0

* exclude vendor/**/* from rubocop target files

* add frozen_string_literal comment line

* fix percent literal delimited by ( and )

* fix alignment

* remove comment disabling unknown cop

application website validation, don't link to app website if website isn't set,
also comment out animated boost icon from #464 until it's consistent with non-animated version

to the API