playbook: don't change default DNS server during vm-bootstrap

The VM will use the DNS server coming from qemu-kvm (see
https://wiki.qemu.org/Documentation/Networking#User_Networking_.28SLIRP.29)
so it will actually use the DNS from the host machine.

playbook/roles/vm-bootstrap/tasks/hostname.yml

@@ -53,12 +53,6 @@
     script: format_hosts /tmp/hosts tl.teralab-datascience.fr 
     when: cluster_hash.stat.exists == True
 
-  - include: resolv_conf.yml
-    when: ansible_distribution != "Ubuntu" or ansible_distribution_major_version|int < 18
-
-  - include: resolv_conf_systemd.yml
-    when: ansible_distribution == "Ubuntu" and ansible_distribution_major_version|int >= 18
-
   - name: Turn off dhclient if it's running
     shell: pkill dhclient
     ignore_errors: True

playbook/roles/vm-bootstrap/tasks/resolv_conf.yml

-  - name: managing resolv.conf file
-    lineinfile: dest=/etc/resolv.conf line="search tl.teralab-datascience.fr"
-
-  - name: adding entry from workspace
-    lineinfile: dest=/etc/resolv.conf line="nameserver 10.200.218.1"
-
-  - name: Delete default nameserver
-    lineinfile: dest=/etc/resolv.conf line="nameserver 10.0.2.3" state=absent
-
-  - name: Delete nameserver 8.8.8.8
-    lineinfile: dest=/etc/resolv.conf line="nameserver 8.8.8.8" state=absent

playbook/roles/vm-bootstrap/tasks/resolv_conf_systemd.yml

-  - name: configuring systemd-resolved (add search)
-    lineinfile: dest=/etc/systemd/resolved.conf line="Domains=tl.teralab-datascience.fr"
-
-  - name: configuring systemd-resolved (add DNS)
-    lineinfile: dest=/etc/systemd/resolved.conf line="DNS=10.200.218.1"
-
-  - name: configuring systemd-resolved (no FallbackDNS)
-    lineinfile: dest=/etc/systemd/resolved.conf line="FallbackDNS="
-    notify: restart systemd-resolved