Yamllint fixes (#4410)

* Lint everything in the repository with yamllint

* yamllint fixes: syntax fixes only

* yamllint fixes: move comments to play names

* yamllint fixes: indent comments in .gitlab-ci.yml file

contrib/dind/roles/dind-host/tasks/main.yaml

@@ -1,3 +1,4 @@
+---
 - name: set_fact distro_setup
   set_fact:
     distro_setup: "{{ distro_settings[node_distro] }}"
@@ -18,7 +19,7 @@
     state: started
     hostname: "{{ item }}"
     command: "{{ distro_init }}"
-    #recreate: yes
+    # recreate: yes
     privileged: true
     tmpfs:
       - /sys/module/nf_conntrack/parameters