Internally compress index bytes

[jameslittle230]

This PR creates a new index serialization format that all new indexes are built with. A new configuration option lets users specify that they want the index data to be compressed (here using bzip2) when written to the output file.

This shrank the Federalist Papers index by a factor of 5x.

Reasons this shouldn't get merged yet:

• [ ] Still some todos in the code to be resolved
• [ ] I'm unsure of the implications for end-user gzipping. Would it be more reliable if the user just gzipped the file themselves?
• [ ] Most importantly, this deadlocks the web browser when indexes get loaded. The WASM binary has to uncompress the data before loading it into memory, and because the WASM executes on the browser's UI thread, the page is frozen during the several seconds it takes to uncompress the data. This is an unacceptable user experience and this PR will probably have to wait until Stork successfully supports running on a web worker. (Fortunately, because of the way the data is saved, the page only has to perform that decompression once upon page load, not once per search)

[codecov[bot]]

Codecov Report

Merging #280 (d42905f) into master (eeaca67) will decrease coverage by 10.67%. The diff coverage is n/a.

@@             Coverage Diff             @@
##           master     #280       +/-   ##
===========================================
- Coverage   72.44%   61.77%   -10.68%     
===========================================
  Files          53       15       -38     
  Lines        2174      518     -1656     
  Branches      104      104               
===========================================
- Hits         1575      320     -1255     
+ Misses        598      197      -401     
  Partials        1        1               

Impacted Files	Coverage Δ
stork-cli/src/clap.rs
stork-cli/src/main.rs
stork-lib/src/config/mod.rs
stork-lib/src/index_v2/mod.rs
stork-lib/src/index_v3/build/errors.rs
stork-lib/src/index_v3/build/fill_containers.rs
...rc/index_v3/build/fill_intermediate_entries/mod.rs
stork-lib/src/index_v3/build/fill_stems.rs
stork-lib/src/index_v3/build/mod.rs
stork-lib/src/index_v3/mod.rs
... and 28 more

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[github-actions[bot]]

Benchmarks

Benchmark	Baseline	Contender	Comparison
build/federalist	229.5537	213.1282	0.93× 🎉
federalist.st	1125.456	271.075	0.24× 🎉
search/federalist/liberty	1.9478	1.9842	1.02×
stork.js	21.961	21.88	1.0×
stork.wasm	356.537	651.157	1.83× ⚠️

Baseline: de70fb01688725b7955aa8a48b4fda7ef8be7993; Comparison: d42905f4b278949c40a002508c550e5c7719e2dd

[jameslittle230]

Closing due to staleness