Fix hard coded versions in XACML-PDP tutorials

Fix hard coded versions in XACML-PDP tutorials

This commit adds variables to the docker-compse file for the
xacml-applicaiton tutorial and adds a startup script that downloads
files fromt  he docker/csit repo to run the tutorial

This commit also removes the separate docker-compose file that was used
for xacml-enforcement tutorial and replaces it with instructions on how
to use the csit docker-compose to run the enforcement.

Issue-ID: POLICY-4186
Change-Id: Id1476e6c0949d3d57bdea9a696b985b60220ec78
Signed-off-by: liamfallon <liam.fallon@est.tech>