Bits and pieces to clean up

[tishun]

Cosmetic changes:

• some of the @since annotations were left out wrong pointing to the (non-existant) Lettuce 7.0 release
• removed the communication part of the README.md as it was mostly repeating the badges
• removed leftovers from the old licensing scheme

Make sure that:

• You have read the contribution guidelines.
• You have created a feature request first to discuss your contribution intent. Please reference the feature request ticket number in the pull request.
• You applied code formatting rules using the mvn formatter:format target. Don’t submit any formatting related changes.
• [] You submit test cases (unit or integration tests) that back your changes.