also switch to dev branch

Update maven Docker tag to v3.8.4

See merge request !12

add snet-abac-server image

See merge request !11

- add image: to template

- rename $IMAGE to $IMAGE_DIR

python, make, gcc and g++ are not required to build this submodule

- abac-server should use https url

- snet-asclepios-context-handler should use relative path

- based on asclepios abac-server image
- adds snet-asclepios-context handler at build time

Update gradle Docker tag to v6.9.1

See merge request !7

tomcat:9-jre8-alpine is no longer maintained

so switch to the same baseimage as here https://github.com/NrgXnat/xnat-docker-compose/blob/master/xnat/Dockerfile

also add comment explaining the the state and entrypoint.sh

make keycloak.json configurable in entrypoint

See merge request !8

* add encPsgAnnontationData type to snet-asclepios-plugin schema
* add button to upload annontations in snet-asclepios-editor
* add route for downloading files in snet-asclepios-search

When switching the submodules remote from AIS to NrgXnat in
6fa8bb2a, I forgot to checkout the appropriate
commit because those two repositories have diverged earlier. The submodule now
points to the current tip of the new remote repo's master branch.