Remove TACACS+ authentication (#15547)

Remove TACACS+ authentication from AWX.

Co-authored-by: Hao Liu <44379968+TheRealHaoLiu@users.noreply.github.com>

tools/docker-compose/ansible/roles/sources/templates/docker-compose.yml.j2

@@ -188,14 +188,6 @@ services:
       - "grafana_storage:/var/lib/grafana:rw"
     depends_on:
       - prometheus
-{% endif %}
-{% if enable_tacacs|bool %}
-  tacacs:
-    image: dchidell/docker-tacacs
-    container_name: tools_tacacs_1
-    hostname: tacacs
-    ports:
-      - "49:49"
 {% endif %}
   # A useful container that simply passes through log messages to the console
   # helpful for testing awx/tower logging