feat!: Improve lua module registration

Instead of having to call all the module registration functions in one
place it is possible for each module to register itself in a global registry.
During startup all the all the modules will be registered
automatically.

This does currently have one weakness, to need to ensure that the crate
is linked.

automation_lib/src/lib.rs

@@ -12,3 +12,26 @@ pub mod lua;
 pub mod messages;
 pub mod mqtt;
 pub mod schedule;
+
+type RegisterFn = fn(lua: &mlua::Lua) -> mlua::Result<mlua::Table>;
+
+pub struct Module {
+    name: &'static str,
+    register_fn: RegisterFn,
+}
+
+impl Module {
+    pub const fn new(name: &'static str, register_fn: RegisterFn) -> Self {
+        Self { name, register_fn }
+    }
+
+    pub const fn get_name(&self) -> &'static str {
+        self.name
+    }
+
+    pub fn register(&self, lua: &mlua::Lua) -> mlua::Result<mlua::Table> {
+        (self.register_fn)(lua)
+    }
+}
+
+inventory::collect!(Module);