Use Rosetta 2 for asdf and brew on Apple M1 setups

What does this Merge Request do?

This MR allows Apple M1 setups to run asdf and brew under Rosetta 2 which allows the GDK to work 🙂 The priority here is to get things working using Rosetta 2 and then as asdf/brew increase their support for the M1 natively we migrate over.

When running a make bootstrap, the following will now appear:

$ make bootstrap
INFO: Performing common preflight checks..
INFO:
INFO: Running the GDK on Apple M1 hardware currently requires running under
INFO: Rosetta 2 until asdf and Homebrew offer native versions of required
INFO: software. For more information on Rosetta 2, please visit:
INFO: https://en.wikipedia.org/wiki/Rosetta_(software)#Rosetta_2
INFO:
INFO: Press [ENTER] to continue..
--snip--

Merge Request checklist

• Tests added for new functionality. If not, please raise Issue to follow-up.
• This change is backward compatible. If not, please include steps to communicate to our users.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.

Closes #1072 (closed)