GitLab

Added new config properties:
* `lms.moodle.teacher-role-ids` (defaults to [3, 4])
* `lms.moodle.student-role-ids` (defaults to [5])

JDBC connectors should be deployed to the Servlet Container separatly.
The dependency is now only used for the embedded development Servlet
container and has been upgraded to version 8.0.x.

Directly use Authentication instead of UserDetails instance.
Authentication has everything we need and works with tests.

* Using Spring Boot Dependencies BOM
* Set up Logback for logging
* Updated dependencies and plugins
* Removed unused dependencies
* Bumped source compatibility to version 1.8

This feature seems to be overkill for the LMS Connector's use case and
has never been used in production.

We remove it because:
* it increased creates code maintenance overhead
* the integrated database increases the the memory footprint

The Ilias connector implementation had an incompatible API and was never
usable with the ARSnova Backend.

:connector-client and :connector-service depend on :connector-model:xjc
task.

statement.

initialization.