style: use deb822 format and remove deprecated apt_key (resolves #2233 / ND-2723)

tasks/install_packages.yml

@@ -14,7 +14,9 @@
     name: [
       'cifs-utils',
       'cpanminus',
+      'gcc',
       'git',
+      'libxml2',
       'make',
       'perl',
       'perl-base',
@@ -51,7 +53,8 @@
     #    - "IO::Handle"
     # and these are not, so they must be installed using cpanm:
     - "Bloom::Filter"
-    - "File::Find"
+    - "File::Find"    # For some reason unknown, this package is not idempotent.
     - "File::Sort"
     - "Path::Tiny"
     - "XML::LibXML::XPathContext"
+  changed_when: false