[Dev] rename iceweasel user profile directory from 'firefox' to 'iceweasel'

[bill-auger]

On Sun, 13 Mar 2022 05:13:55 -0400 bill-auger wrote:
> the original rationale may have also been to ease with migration
> from arch - the change i added to the PKGBUILD handles that case
> also (when `which firefox`, the profile is copied instead of
> moved)

derp - just realized that would never be the case - by the time
'iceweasel' is installed, 'firefox' has (most likely) been
removed by 'your-freedom'