buildsystem: Move to meson for building the project

Meson will allow us to:
- Verify the used rust compiler is recent enough
- Install ressources such as a .desktop files, icons, etc.

build-aux/org.freedesktop.ryuukyu.Helvum.json

@@ -0,0 +1,38 @@
+{
+    "app-id": "org.freedesktop.ryuukyu.Helvum",
+    "runtime": "org.gnome.Platform",
+    "runtime-version": "40",
+    "sdk": "org.gnome.Sdk",
+    "sdk-extensions": [
+        "org.freedesktop.Sdk.Extension.rust-stable"
+    ],
+    "command": "helvum",
+    "finish-args": [
+        "--socket=fallback-x11",
+        "--socket=wayland",
+        "--device=dri",
+        "--share=ipc",
+        "--filesystem=xdg-run/pipewire-0"
+    ],
+    "build-options": {
+        "append-path": "/usr/lib/sdk/rust-stable/bin",
+        "build-args": [
+            "--share=network"
+        ]
+    },
+    "modules": [
+        {
+            "name": "Helvum",
+            "buildsystem": "meson",
+            "sources": [
+                {
+                    "type": "dir",
+                    "path": "../"
+                }
+            ],
+            "config-opts": [
+                "-Dprofile=development"
+            ]
+        }
+    ]
+}