rename api3 back to api2

There is no real need to change the path, so using api2 we can reuse
all helpers (like tools from proxmox widget toolkit).

src/api2/version.rs

@@ -0,0 +1,28 @@
+use failure::*;
+
+use crate::api::schema::*;
+use crate::api::router::*;
+use serde_json::{json, Value};
+
+const PROXMOX_PKG_VERSION: &'static str = env!("PROXMOX_PKG_VERSION");
+const PROXMOX_PKG_RELEASE: &'static str = env!("PROXMOX_PKG_RELEASE");
+const PROXMOX_PKG_REPOID: &'static str = env!("PROXMOX_PKG_REPOID");
+
+fn get_version(_param: Value, _info: &ApiMethod) -> Result<Value, Error> {
+
+    Ok(json!({
+        "version": PROXMOX_PKG_VERSION,
+        "release": PROXMOX_PKG_RELEASE,
+        "repoid": PROXMOX_PKG_REPOID
+    }))
+}
+
+pub fn router() -> Router {
+
+    let route = Router::new()
+        .get(ApiMethod::new(
+            get_version,
+            ObjectSchema::new("Proxmox Backup Server API version.")));
+
+    route
+}