As a user, I want to discover available template-sets and be able to choose one of them to be installed so that I can take my choice and start development.

Initial thoughts for a screen have been made in #1453.

Acceptance Criteria:

• core should implement a simple UI (JavaFX), which should list discovered template sets from (all configured - separate story Enable custom template-set groupIds for lookup #1511 and Discovery of template sets #1517) remote sources
• the UI should show me a description of each template-set and the current status, whether it is already installed or not (versioning will be handled in Ability to manage template-sets and template-set status #1512)
• on click of an installation button, the template-set should be installed into the currently active configuration folder