PyCA 3.0

This is the release 3.0 of PyCA.

Version 3.0 is introducing a new [Vue.js](https://vuejs.org/) based UI and
monitoring as well as dropping Python 2 and fixing some different issues.

Features
--------

- New UI Reload. Instead of serving a static page and triggering the browsers reload,
  the new UI is now an [Vue.js](https://vuejs.org/) app and reloads only the resources
  in the background via the JSON API.
  This includes also a JavaScript dependency management via npm.

- Drop Python 2 support.

- Introduction of a monitoring section in the UI where different metrics about
  the pyCA services themself, but also the underlying machine are displayed.
  The metrics are exposed via a new API endpoint `/api/metrics`

- Switch from configuration file to configuration directory to provide a folder
  for other corresponding configuration files like Gunicorn configuration.

- New wrapper method for database sessions to ensure proper session handling.

- Revised service files. We introduced a new service file to make starting and
  stopping of all pyca services easier and changed some commands to make the
  service files more usable across multiple OS. #183

Bug Fixes
---------

- Fix to prevent caching from Preview images in Chrome Browser.

- Fix that interrupted recording commands could lead to a loop of errors while
  trying to start the recording again. #137

- Multiple fixes in the documentation. We updated the installation guides,
  service files and reverse proxy examples.

- Fix SQLite Threading Problem in development flask server by disabling threading.

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name="pyca",
-    version="2.2",
+    version="3.0",
     description="Opencast Capture Agent",
     author="Lars Kiesow",
     author_email='[email protected]',