Update groups and role-composites

Features:

• Add, update and delete groups
• Add, update und delete role-composites

Further changes:

• Upgrade to OpenJDK/Java 11

Supported Keycloak Versions:

• 9.0.0
• 8.0.x

Support for Keycloak 9.0

This release supports following Keycloak versions:

• 9.0.0
• 8.0.x

Keycloak 8.0.2

Updating Keycloak API to 8.0.2

Support for Keycloak 8.0

From this release keycloak-tool supports Keycloak 8.0.x only.
I had to remove the support for older versions due to REST interface incompatibilities.

First release

This version supports following Keycloak versions:

• 7.0.0
• 6.0.x
• 5.0.0
• 4.8.x
• 4.7.0
• 4.6.0
• 4.5.0
• 4.4.0