Add Gazelle to Web Framework Benchmarks (TechEmpower)

[mj41-gdc]

See

• https://www.techempower.com/benchmarks/
• and Perl implementations https://github.com/TechEmpower/FrameworkBenchmarks/tree/master/frameworks/Perl

Thank you.

[bbrtj]

I added Gazelle as one of the web servers for Kelp, so I would consider this issue resolved.