Design a skeleton for a framework support auto instrumentation

- Decide what information framework-supporting auto instrumentation part should provide
- Capture route info to derive transaction name
- Discover service name/version
- Capture user info for transaction's context.user (although it might be worth investigating if it's possible to capture user info in some centralized not framework-specific way)
- Detect if request completed with an error (for example whether exception escaped from top level application specific code into framework code)

- Refactor currently already existing support for CLI script and PHP CLI built-in HTTP server as auto instrumentation components following the designed skeleton.