huge performance hit after tantivy integration

[naturallymitchell]

why?

[dariusc93]

could there be some benchmarks testing before and after to show how big of a hit there is?

[Arnaz87]

Benchmark: wrk -t12 -c400 -d30s http://localhost:3000, result is requests per second (the bigger the better)

Lighttouch, without homepage-package, with the regular lighttouch-base version with tantivy and torchbear with tantivy enabled: 43.79 Requests/sec

Lighttouch, without homepage-package, with a lighttouch-base version without tantivy, and torchbear with tantivy commented: 929.90 Requests/sec

That's 20x faster for the build without tantivy.

I'll update these benchmarks later with the commit hashes, and also I'd like to include a benchmark with the same lighttouh-base version but with tantivy enabled and disabled in torchbear

[naturallymitchell]

tantivy moved to cfg.feature for now