Enhance k3s_agent role with idiomatic Ansible practices for better maintainability.

**Added:**

- Structured HTTP Proxy Configuration Block - Added a structured block in
  `http_proxy.yml` for managing HTTP proxy settings, aligning with Ansible's
  recommended practices. This includes creating directories and deploying
  configuration files in a clear, modular fashion.
- Conditional Execution for Proxy Setup - Implemented conditional execution
  for the proxy setup in `http_proxy.yml`, utilizing `proxy_env` to adhere
  to Ansible's best practices for conditional tasks.
- Improved PXE-Boot System Check Block - Introduced a more structured approach
  in `main.yml` for checking PXE-booted systems, enhancing readability and
  maintainability.

**Changed:**

- Adopted Ansible Builtin Modules - Transitioned existing tasks to use
  `ansible.builtin` modules, ensuring compatibility and future-proofing the
  role.
- Refined Task Grouping - Reorganized tasks into logical blocks, improving
  the overall structure and readability, and showcasing Ansible's capabilities
  for efficient task management.
- Updated K3s Service Configuration - Modified the K3s service configuration
  task in `main.yml` for a more streamlined approach using Ansible's template
  module, reflecting community-driven best practices.

**Removed:**

- Streamlined Task Definitions - Optimized task definitions to reduce
  redundancy, focusing on clarity and adherence to the evolving Ansible
  community standards.

roles/k3s_agent/tasks/http_proxy.yml

@@ -1,16 +1,17 @@
 ---
-
+- name: Manage K3s HTTP Proxy Configuration
+  when: proxy_env is defined
+  block:
     - name: Create k3s.service.d directory
-  file:
+      ansible.builtin.file:
         path: '{{ systemd_dir }}/k3s.service.d'
-    state: directory
         owner: root
         group: root
+        state: directory
         mode: '0755'
 
-
+    - name: Deploy the K3s http_proxy configuration file
-- name: Copy K3s http_proxy conf file
+      ansible.builtin.template:
-  template:
         src: "http_proxy.conf.j2"
         dest: "{{ systemd_dir }}/k3s.service.d/http_proxy.conf"
         owner: root

roles/k3s_agent/tasks/main.yml

@@ -1,29 +1,32 @@
 ---
+- name: Check for PXE-booted system
+  block:
     - name: Check if system is PXE-booted
-  command: cat /proc/cmdline
+      ansible.builtin.command:
+        cmd: cat /proc/cmdline
       register: boot_cmdline
       changed_when: false
+      check_mode: false
 
     - name: Set fact for PXE-booted system
-  set_fact:
+      ansible.builtin.set_fact:
         is_pxe_booted: "{{ 'root=/dev/nfs' in boot_cmdline.stdout }}"
-  when: boot_cmdline is defined
+      when: boot_cmdline.stdout is defined
 
-- name: Deploy K3s http_proxy conf
+    - name: Include http_proxy configuration tasks
-  include_tasks: http_proxy.yml
+      ansible.builtin.include_tasks: http_proxy.yml
-  when: proxy_env is defined
 
-- name: Copy K3s service file
+- name: Configure the k3s service
-  template:
+  ansible.builtin.template:
     src: "k3s.service.j2"
     dest: "{{ systemd_dir }}/k3s-node.service"
     owner: root
     group: root
-    mode: 0755
+    mode: '0755'
 
-- name: Enable and check K3s service
+- name: Manage k3s service
-  systemd:
+  ansible.builtin.systemd:
     name: k3s-node
-    daemon_reload: yes
+    daemon_reload: true
     state: restarted
-    enabled: yes
+    enabled: true