feat(reverse_proxy): add Netcup DNS ACME challenge support and refactor Caddy setup

Signed-off-by: Tuan-Dat Tran <tuan-dat.tran@tudattr.dev>

roles/reverse_proxy/tasks/20_xcaddy_install.yml

@@ -0,0 +1,32 @@
+---
+- name: Download xCaddy GPG key
+  ansible.builtin.get_url:
+    url: "https://dl.cloudsmith.io/public/caddy/xcaddy/gpg.key"
+    dest: /etc/apt/keyrings/caddy-xcaddy.asc
+    mode: "0644"
+  become: true
+
+- name: Add xCaddy repository to apt sources
+  ansible.builtin.apt_repository:
+    repo: "deb [signed-by=/etc/apt/keyrings/caddy-xcaddy.asc] https://dl.cloudsmith.io/public/caddy/xcaddy/deb/debian any-version main"
+    state: present
+    update_cache: true
+  become: true
+
+- name: Update apt cache
+  ansible.builtin.apt:
+    update_cache: true
+  become: true
+
+- name: Install xCaddy
+  ansible.builtin.apt:
+    name: xcaddy
+    state: present
+  become: true
+
+- name: Build Custom Caddy with netcup
+  ansible.builtin.command: xcaddy build --with github.com/caddy-dns/netcup {{ reverse_proxy_caddy_version}}
+  environment:
+    PATH: "{{ ansible_env.PATH }}:/usr/local/go/bin"
+  register: xcaddy_build
+  failed_when: xcaddy_build.rc != 0