Simplify macOS related bits in Firefox project
#30323 (moved) included already simplifications made in https://bugzilla.mozilla.org/show_bug.cgi?id=1513798 but not all of them due to breakage. We should follow-up on that and bring our compile instructions closer to what Mozilla is deploying.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information