isolated ramparts: replace systemd unit with a tower-expect binary

instead of launching isolated tasks via `systemctl`, treat
`awx.main.isolated.run` as an executable that knows how to daemonize

additionally, add `setup.py isolated_build` for isolated Tower source
distribution

awx/playbooks/check_isolated.yml

@@ -16,13 +16,6 @@
         mode: pull
         recursive: yes
 
-    - name: check to see if the job is inactive
-      command: "systemctl is-active playbook@{{job_id}}.service"
-      register: is_active
-      failed_when: "is_active.rc == 0"
-
-    - shell: journalctl -u playbook@{{job_id}}.service --no-pager
-      register: systemctl_logs
-      ignore_errors: True
-
-    - local_action: copy content={{ systemctl_logs.stdout }} dest={{src}}/artifacts/systemctl_logs mode=0600
+    - shell: "tower-expect is-alive {{job_id}}"
+      register: is_alive
+      failed_when: "is_alive.rc == 0"

awx/playbooks/clean_isolated.yml

@@ -10,7 +10,7 @@
   tasks:
 
     - name: cancel the job
-      command: "systemctl stop playbook@{{job_id}}.service"
+      command: "tower-expect stop {{job_id}}"
       ignore_errors: yes
 
     - name: remove build artifacts

awx/playbooks/run_isolated.yml

@@ -36,7 +36,7 @@
       command: "mkfifo /tmp/ansible_tower/jobs/{{job_id}}/env"
 
     - name: spawn the playbook
-      command: "systemctl start playbook@{{job_id}}.service"
+      command: "tower-expect start {{job_id}}"
 
     - name: write the secret environment data
       mkfifo: