Add git hook suggestions for Arm development (#7785)

Pre-commit runs lintrunner on commited files,
tries applying the changes.
Pre-push does not push if lintrunner or
a simple license check does not pass.

If WIP is included in commit header,
no checks are done.

setup-env.sh symlinks the hooks to your
.git/hooks.

install-editable.sh contains commands needed to
do an editable install.

Signed-off-by: Erik Lundell <erik.lundell@arm.com>