Feature/version in config (#376)

* Added version field to config files

* Removed built dependency

* Missing non-removed call to built

mixnode/src/node/presence.rs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::built_info;
 use directory_client::presence::mixnodes::MixNodePresence;
 use directory_client::DirectoryClient;
 use log::{error, trace};
@@ -66,7 +65,7 @@ impl Notifier {
             pub_key: config.pub_key_string,
             layer: config.layer,
             last_seen: 0,
-            version: built_info::PKG_VERSION.to_string(),
+            version: env!("CARGO_PKG_VERSION").to_string(),
         };
         Notifier {
             net_client,