add(ui/ux): show the running version and build stamp in the header

Dockerfile

@@ -6,8 +6,10 @@ COPY wordarr ./wordarr
 COPY static ./static
 RUN pip install --no-cache-dir .
 
+ARG WORDARR_BUILD=""
 ENV WORDARR_CONFIG_DIR=/config \
-    WORDARR_DOWNLOAD_DIR=/mnt/downloads
+    WORDARR_DOWNLOAD_DIR=/mnt/downloads \
+    WORDARR_BUILD=$WORDARR_BUILD
 
 VOLUME /config
 EXPOSE 8787