Remove Mozilla branding

This merge requests removes most public 'Mozilla' and 'Firefox' branding and renames the application from 'Firefox Send' to 'Send'.

This is useful to allow to legally self-host Send, as 'Mozilla' and 'Firefox' are trademarks.

enabled an automatic merge when the pipeline for f035132b succeeds

mentioned in commit 0dd4f8d2

merged

changed the description