Support both binary & source install, improved README, fixed systemd service etc.

tasks/main.yml

@@ -20,10 +20,10 @@
   vars:
     __os_supported: "{{ lookup('vars', '{}_os_supported'.format(role_name)) | bool }}"
 
-- name: Assert matrixmailer version and system_spec are defined
+- name: Assert matrixmailer version and build are defined
   assert:
-    that: matrixmailer_version is defined and matrixmailer_system_spec is defined and matrixmailer_config is defined
-    fail_msg: "The ansible variables 'matrixmailer_version', 'matrixmailer_system_spec' and 'matrixmailer_config' need to be set to run this role."
+    that: matrixmailer_version is defined and matrixmailer_build is defined and matrixmailer_config is defined
+    fail_msg: "The ansible variables 'matrixmailer_version', 'matrixmailer_build' and 'matrixmailer_config' need to be set to run this role."
 
 - name: Create matrixmailer group
   group:
@@ -40,14 +40,49 @@
     password_lock: yes
     state: present
 
-- name: Download matrixmailer
-  become: yes
-  get_url:
-    url: "https://gitea.a-0.me/philip/matrixmailer/releases/download/{{ matrixmailer_version }}/{{ matrixmailer_system_spec }}"
-    dest: "{{ matrixmailer_binary_location }}"
-    owner: "{{ matrixmailer_system_user }}"
-    group: "{{ matrixmailer_system_group }}"
-    mode: 0500
+- name: Install matrixmailer from pre-built binary
+  block:
+    - name: Download matrixmailer
+      become: yes
+      get_url:
+        url: "https://gitea.a-0.me/philip/matrixmailer/releases/download/{{ matrixmailer_version }}/{{ matrixmailer_build }}"
+        dest: "{{ matrixmailer_binary_location }}"
+        owner: "{{ matrixmailer_system_user }}"
+        group: "{{ matrixmailer_system_group }}"
+        mode: 0500
+  when: matrixmailer_build != "from_source"
+
+- name: Install matrixmailer custom-built from git repository
+  block:
+    - name: Clone repository
+      git:
+        repo: "{{ matrixmailer_git_repo }}"
+        depth: 1
+        dest: "{{ matrixmailer_build_tmp }}"
+        version: "{{ matrixmailer_git_branch }}"
+    - name: Install required packages
+      apt:
+        pkg:
+          - libssl-dev
+          - pkg-config
+          - curl
+        state: present
+    - name: Install Rust
+      command:
+        cmd: "curl https://sh.rustup.rs -sSf | sh"
+    - name: Install matrixmailer
+      command:
+        cmd: cargo build --release
+        chdir: "{{ matrixmailer_build_tmp }}"
+    - name: Copy built binary to final location
+      copy:
+        remote_src: yes
+        src: "{{ matrixmailer_build_tmp }}"/release/matrixmailer
+        dest: "{{ matrixmailer_binary_location }}"
+        owner: "{{ matrixmailer_system_user }}"
+        group: "{{ matrixmailer_system_group }}"
+        mode: 0500
+  when: matrixmailer_build == "from_source"
 
 - name: Create config file directory
   file: