Provide API on Camel Kafka Connector to add/remove connectors dynamically

[apupier]

This is useful in 2 cases for providing tooling:

• allow users to provide their own connectors to the catalog and leverage the Tooling support
• allow to add easily dynamically connectors for testing purpose for Tests of Camel Tooling

I will provide a Pull request

[oscerd]

Resolved through #574