Jetty 9.4.20 has a breaking change causing issues with Spring's
Websocket handling. This will be fixed in version 9.4.21.

See https://github.com/eclipse/jetty.project/issues/4020.

Closes #49.

The Spring Platform BOM has reached EOL, so we need to replace it for
future updates. This should not change any dependency versions.

https://spring.io/blog/2018/04/09/spring-io-platform-end-of-life-announcement

See GH-65.

* Update MathJax URL to use version 2.7.5
* Piwik was renamed to Matomo

Add support for OpenID Connect authentication

See merge request !118

Only OIDC providers that support configuration discovery are supported.

Google OIDC

See merge request !117

Google shuts down its Google+ Sign-In.

Add API endpoint to create copies of public pool sessions

See merge request !116

Fix import format

See merge request !115

The field of the inner class is kept for compatibilty reasons.

Delete inactive users

See merge request !102