Test/tweak Linux support

[Jonathan Bossenger]

Mostly, this should already work on a Linux desktop, but it needs to be tested.

We will test with Ubuntu only for now.

[Jonathan Bossenger]

Replace the section that relies on osascript on the Mac and use Python on Linux

INSTANCE_DATA=$( multipass info --format json wp-local-env )
read -r -d '' JXA <<EOF
function run() {
	var info = JSON.parse(\`$INSTANCE_DATA\`);
	return info.info["wp-local-env"].ipv4;
}
EOF
INSTANCE_IP=$( osascript -l 'JavaScript' <<< "${JXA}" )

See also : https://stackoverflow.com/questions/1955505/parsing-json-with-unix-tools