apparmor/automated: Simplify installation and test procedure

Previously, we computed RESOURCE_DIR from a sourced shell
script fragment that is edited by `make` during install. This is
much more complexity than we actually needed, because in practice
we were locating RESOURCE_DIR from $0 anyway.

Make it a lot simpler by removing the Makefile, not invoking a
sub-make in the apparmor/automated/ directory, and not indirecting
through sourced shell script fragments to calculate RESOURCE_DIR.

TESTDATADIR, TESTLIBDIR and MEDIA_RESOURCE_DIR are not used in this
particular test. We can make that very obvious by just deleting them.

The Makefile previously installed into both /usr/lib/apertis-tests
(via COPY; packaged into apertis-tests) and /usr/share/chaiwala-tests
(via SUBDIRS; packaged into the legacy chaiwala-tests package).
The official test instructions on the Apertis wiki called for this
test to be run via /usr/share/chaiwala-tests until very recently,
so install a transitional symbolic link in chaiwala-tests.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Emanuele Aina <emanuele.aina@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D6917