feat(role): Add package-specific global config files

Packages can now have a global (i.e. system-wide) config defined and
applied. If package is missing the config file is deleted. This is
helpful for example for Git where we want to define helpful aliases
for every logged in user and for tmux where every user should have
access to the tmux-resurrect session manager etc.

tasks/base-package-auxiliary-settings-single-package-single-config.yml

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: MIT
+
+# This file adds config blocks to files that are dependent on a single package
+# being present. If for example the 'git' package is present we want content in
+# Git's global '/etc/gitconfig' file. If the package is absent that file content
+# is removed. If after that the file is empty (i.e. has a size of 0 bytes) the
+# file is deleted.
+
+- name: 'Add per-package config'
+  when: 'pkg.name in ansible_facts.packages'
+  loop_control:
+    loop_var: 'pkg'
+    label: 'If ''{{ pkg.name }}'' package is present set system-wide config in ''{{ pkg.global_config_file }}'''
+  loop: '{{ package_config }}'
+  ansible.builtin.blockinfile:
+    marker: '# {mark} ANSIBLE MANAGED BLOCK - {{ pkg.name }} {{ pkg.marker }}'
+    path: '{{ pkg.global_config_file }}'
+    append_newline: true
+    prepend_newline: true
+    state: 'present'
+    create: true
+    block: '{{ pkg.global_config }}'
+
+- name: 'Get stats of global config files'
+  register: 'role_common_packages__global_config_file_stats'
+  loop_control:
+    loop_var: 'pkg'
+    label: 'Get stats of ''{{ pkg.name }}'' system-wide config file ''{{ pkg.global_config_file }}'''
+  loop: '{{ package_config }}'
+  ansible.builtin.stat:
+    path: '{{ pkg.global_config_file }}'
+
+- name: 'Remove per-package config'
+  when: 'stat_result.pkg.name not in ansible_facts.packages'
+  loop_control:
+    loop_var: 'stat_result'
+    label: 'If ''{{ stat_result.pkg.name }}'' package is absent and system-wide config file ''{{ stat_result.pkg.global_config_file }}'' is present remove config file'
+  loop: '{{ role_common_packages__global_config_file_stats.results }}'
+  ansible.builtin.file:
+    path: '{{ stat_result.pkg.global_config_file }}'
+    state: 'absent'