clean up foobazdmx role

make git repo url and version to check out a variable instead of a
hard-coded value the role, and update host_vars to match.

inventories/z9/host_vars/light.yaml

@@ -1,3 +1,6 @@
+foobazdmx__art_net_host: localhost
+foobazdmx_version: main
+foobazdmx_repo_url: "https://ccchh-ansible:glpat-istRKj5ivdBs_u9Tsdbp@gitlab.hamburg.ccc.de/ccchh/foobazdmx.git"
 ola__configs:
   - name: ola-artnet
     content: "{{ lookup('ansible.builtin.file', 'configs/light/ola/ola-artnet.conf') }}"
@@ -47,7 +50,6 @@ ola__configs:
     content: "{{ lookup('ansible.builtin.file', 'configs/light/ola/ola-usbdmx.conf') }}"
   - name: ola-usbserial
     content: "{{ lookup('ansible.builtin.file', 'configs/light/ola/ola-usbserial.conf') }}"
-foobazdmx__art_net_host: localhost
 nginx__version_spec: ""
 nginx__deploy_redirect_conf: false
 nginx__configurations: