allow for dynamic runner description

Previously the Runner description was hard coded. Now it is possible to
set it dynamically via an ansible fact.

roles/gitlab-runner/tasks/main.yml

@@ -29,7 +29,7 @@
     body_format: form-urlencoded
     body:
       name: "{{ ansible_fqdn }}"
-      description: "virtual machine on {{ ansible_fqdn }}"
+      description: "{{ ansible_local.gitlab_runner.description }}"
       token: "{{ ansible_local.gitlab_runner.registration_token }}"
       tag_list: "{{ ansible_local.gitlab_runner.tags }}"
     status_code: 201

roles/gitlab-runner/templates/gitlab_runner.fact

@@ -3,5 +3,6 @@
   "runner_token": "{{ runner_token.content | from_json | json_query('token') }}",
   "gitlab_domain": "{{ ansible_local.gitlab_runner.gitlab_domain }}",
   "executor": "{{ ansible_local.gitlab_runner.executor }}",
+  "description": "{{ ansible_local.gitlab_runner.description }}",
   "tags": "{{ ansible_local.gitlab_runner.tags }}"
 }