Rethink annotation design for better maintainability

CCM currently employs a set of annotations to control LBs. While these were easy to handle initially, nowadays they are becoming more and more challenging to maintain both for CCM developers and consumers; this is mostly due to the way they may (sometimes should) interact with each other. One example is how (secure) protocols affect specified ports and the corresponding validation.

We should think about alternative approaches to configuring LBs.

Versioning-wise, we should probably take the opportunity to introduce a breaking change as we promote CCM to v1 (which does not mean that we are going to deprecate the old, annotation-based approach for sure; more likely, we're going to continue supporting it but add new configuration features to v1 only).