chore(benchmarks): New benchmarks

This is a suite of benchmarks measuring performance of various parts of DI. Includes benchmarks measuring time of:
- Creating objects manually without DI
- Creating an injector
- Creating a child injector
- Using a simple injector with basic features only
- Precompute keys

These benchmarks provide an idea of potential improvements by providing a baseline comparison of time requirements for certain actions.

Additionally included is large_benchmark.dart which creates a large tree of injectors to measure memory consumption.