Simplifying Tggl to enforce good practices

Tggl is undergoing a transition to improve its feature flag management by eliminating the concept of fallback variations, which had created confusion among users due to its dual solutions for error handling. Initially, Tggl's design included fallback variations to ensure system resilience during unexpected events, such as network errors or missing API keys. However, this approach led to user confusion, requiring explanations about the difference between active and fallback variations. Effective December 16, 2024, new Tggl feature flags will only include active variations with explicit values, streamlining the process and simplifying the learning curve for users. This change enforces good practices by providing a single solution for handling feature flags, making the defaultValue argument mandatory, and updating all SDKs accordingly. Existing flags can continue under the old paradigm unless users choose to update them, while new accounts will automatically adopt the new system. The transition is designed to be smooth, with comprehensive documentation updates and support for users who wish to adapt their existing flags to the new paradigm.