tests: Bluetooth: Audio: Modify/add compile.sh for audio samples

Instead of having one large compile.sh for all audio samples,
it has been split into multiple. This makes it easier to
build and run specific tests (e.g. BAP or CAP), without
having to build all of them.

This also makes it easier to expand later, without
creating one huge compile.sh file.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>