Implement basic Load Testing functionality

[Badgerati]

Implement basic features of load testing into Edison. This could be done using different fixture/test attributes such as [LoadTestFixture] and [LoadTest], where [LoadTest]` accepts a seconds-to-run, and max-rps.

These tests will be run completely separate to number tests for stability, lightweight running. They will also run sequentially.

For example:

[LoadTest(30, 100)]
public void Test()
{
    //call some URL
}

This will call some URL, rapidly, for 30 seconds with a simulated 100 requests per second maximum. There could even be a configurable delay between each call.

After each load test has finished report:

• Minimum response time
• Maximum response time
• Average response time
• Total number of requests
• Total successful requests
• Total failed requests

The timing will basically be how long that "test" took to complete, and same for number of requests being number of tests.