add docker_use_dist_repo variable + default

to decide for install source repo
and add to README

roles/docker/defaults/main.yml

@@ -0,0 +1,2 @@
+---
+docker_use_dist_repo: false

roles/docker/tasks/main.yml

@@ -1,4 +1,4 @@
 ---
 - name: include proper install tasks
   ansible.builtin.import_tasks:
-    file: "{{ docker_type | default('docker') }}.yml"
+    file: "{{ 'dist' if docker_use_dist_repo else 'docker' }}.yml"