added rate checker test to use queries from csv file

- Updated Readme with info on how to install/run Jmeter load tests
- Made the ramp up time and loop count configurable from the command line
- Added csv file with 3 rows of Rate Checker queries to use for now, we can add more queries by adding more rows to the csv file
- The rate checker is a separate load test so we have the flexibility to run the rate checker load test with a different number of users than the landing pages