Add some WASM APIs

[matheus23]

• Provide metadata info in ls
• Expose base_history_on function
• Expose load function

Fixes #34

[codecov-commenter]

Codecov Report

Merging #39 (6fd56b9) into main (0a6d8b6) will increase coverage by 2.96%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #39      +/-   ##
==========================================
+ Coverage   77.11%   80.07%   +2.96%     
==========================================
  Files          17       18       +1     
  Lines         970     1275     +305     
==========================================
+ Hits          748     1021     +273     
- Misses        222      254      +32     

Impacted Files	Coverage Δ
crates/fs/common/metadata.rs	68.18% <ø> (ø)
crates/wasm/fs/public/directory.rs	0.00% <ø> (ø)
crates/fs/common/error.rs	0.00% <0.00%> (-50.00%)	⬇️
crates/fs/private/hamt/hash.rs	97.22% <0.00%> (-2.78%)	⬇️
crates/fs/private/hamt/pointer.rs	66.15% <0.00%> (-2.14%)	⬇️
crates/wasm/fs/blockstore.rs	0.00% <0.00%> (ø)
crates/fs/private/hamt/error.rs
crates/fs/private/namefilter/bloomfilter.rs	88.88% <0.00%> (ø)
crates/fs/private/namefilter/namefilter.rs	90.90% <0.00%> (ø)
... and 4 more

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[appcypher]

Thanks for tackling these problems. I have a few comments on some of type conversions. They are just idiom nitpicks.

[matheus23]

Ok, should be good to go. Mind giving this another look @appcypher?

I don't really like the sed-based hacks in the rs-wnfs script, but it works. I think I want to do something that bypasses wasm-pack at some point, so we have more control over the generated package.json. But that'll be another PR.

[appcypher]

Looks great! 🎉