Install gnupg before adding docker apt gpg key during pre-install

Adding docker apt gpg key requires gpupg to be installed.
Task will fail on minimal Debian 10 install as gnupg absent.

Change-Id: I979f88162ad8a206e413b37ac7fb09bcc912e016

ansible/roles/baremetal/tasks/pre-install.yml

@@ -81,7 +81,7 @@
             update_cache: yes
           become: True
 
-        - name: Install ca certs
+        - name: Install CA certificates and gnupg packages
           package:
             name: "{{ item }}"
             state: latest
@@ -89,6 +89,7 @@
           with_items:
             - ca-certificates
             - apt-transport-https
+            - gnupg
 
         - name: Ensure apt sources list directory exists
           file: