S allius/issue397 (#405)

* add Dashboards log handler to all known loggers

* add list of last 3 warnings/errors to page

* add note list to page

* create LogHandler for the dashboard

- simple memory log handler which stores the last
  64 warnings/errors for the dashboard

* render warnings/errors as note list

* add page for warnings and errors

* fix double defined build target

* add well done message if no errors in the logs

* translate page titles

* more translations

* add Notes page and table for important messages

* add unit tests

app/src/web/pages.py

@@ -18,6 +18,13 @@ async def mqtt():
         fetch_url=url_for('.mqtt_fetch'))
 
 
+@web.route('/notes')
+async def notes():
+    return await render_template(
+        'page_notes.html.j2',
+        fetch_url=url_for('.notes_fetch'))
+
+
 @web.route('/logging')
 async def logging():
     return await render_template(