Benchmarks for measure the performance of Open ETP Server

I'd like to introduce benchmarks for Open ETP server, this will help to:

• Measure the performance of server/client interaction and individual components
• Test stability in high-load multi-threading scenarios
• Help to control the performance when refactoring code

Based on well known library Google benchmark. Current implementation includes 44 benchmarks that cover most used components and APIs.

Get more information from README.md