WIP: start ripping out args (MR 2252)

Cease merging pmbootstrap.cfg into args, implement a Context type to let
us pull globals out of thin air (as an intermediate workaround) and rip
args out of a lot of the codebase.

This is just a first pass, after this we can split all the state that
leaked over into Context into types with narrower scopes (like a
BuildContext(), etc).

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

pmb/parse/arch.py

@@ -5,9 +5,6 @@ import platform
 import pmb.config
 import pmb.parse.arch
 
-from pmb.core.types import PmbArgs
-from pmb.core import Chroot, ChrootType
-
 def alpine_native():
     machine = platform.machine()