feat: request cancellation

[logaretm]

This PR brings AbortController support to cancel ongoing requests.

Aside from that, if the same query/mutation triggered multiple requests, it will be canceled by default.

The only problem is to workout the interaction between cancellation and dedup and batch plugins.

For dedup it is problematic to cancel a deduped request because that means it would cancel for other queries as well. There isn't a lot of options here other than "avoid" deduped requests abort signal to prevent mistakes.

For batch, that would cancel the whole batched request. I don't think I have much choice here other than not supporting cancellation with batch.

closes #90

[codecov-commenter]

Codecov Report

Merging #106 (dc4a99a) into main (319dd44) will decrease coverage by 2.16%.
The diff coverage is 70.21%.

@@            Coverage Diff             @@
##             main     #106      +/-   ##
==========================================
- Coverage   94.67%   92.51%   -2.17%     
==========================================
  Files          26       26              
  Lines         526      561      +35     
  Branches       94      106      +12     
==========================================
+ Hits          498      519      +21     
- Misses         28       42      +14     

Impacted Files	Coverage Δ
packages/villus/src/utils/common.ts	80.00% <50.00%> (-12.86%)	⬇️
packages/villus/src/fetch.ts	96.00% <66.66%> (-4.00%)	⬇️
packages/villus/src/useMutation.ts	84.21% <68.75%> (-12.09%)	⬇️
packages/villus/src/useQuery.ts	91.35% <72.22%> (-5.71%)	⬇️
packages/villus/src/client.ts	100.00% <100.00%> (ø)
packages/villus/src/utils/error.ts	93.75% <100.00%> (+0.41%)	⬆️

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