wip: implement (Un)MarshalJSON(Amino) TypedValue

[gfanton]

Work in Progress

This pull request aims to implement JSON marshaling on TypedValue. It includes:

• A lower-level encoding API for writing/reading JSON. The code is mostly taken from protojson, which provides a generic enough API, is well-tested, and does not rely on reflection or other libraries. I have made slight updates to the code to avoid unnecessary randomness or depends on protobufs.
  • If needed, we can update this part later with a more optimised encoder for Gno or adapt this one to use reader/writer instead of raw []byte data, for example.
• (Un)MarshalJSON(Amino) methods on TypedValue
• (Un)MarshalOptions that allow passing additional options like Store and Allocator (optional)

Current State:

• Support scalar types (bool, number, string)
• Support Array
• Support object (struct)
• Partially support Interface
• Handle circular reference with objectid

Note: Don't be scared by the number of lines added. The most important parts of the code are located in value_json.go and value_json_test.go, as encoding/json/* is mostly taken from protojson.

TODO:

• RefValue support
• Fully support Amino format
• More tests
• Documentation & Comments
• ... (Possibly other tasks, I will add them later as I discover them)

Contributors' checklist...

• Added new tests, if necessary or feasible
• Provided an example (e.g. screenshot) to assist in the review or ensured the PR is self-explanatory
• Updated the official documentation, if required
• No breaking changes were introduced, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided useful hints for running manual tests
• Added new benchmarks to generated graphs, if applicable. More information here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.11%. Comparing base (e844fc1) to head (5921ac2).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2652      +/-   ##
==========================================
- Coverage   60.12%   60.11%   -0.01%     
==========================================
  Files         560      560              
  Lines       74690    74690              
==========================================
- Hits        44905    44900       -5     
+ Misses      26397    26396       -1     
- Partials     3388     3394       +6     

Flag	Coverage Δ
contribs/gnodev	61.40% <ø> (ø)
contribs/gnofaucet	14.46% <ø> (-0.86%)	⬇️
gno.land	64.15% <ø> (ø)
misc/genstd	80.54% <ø> (ø)
misc/logos	19.88% <ø> (ø)
tm2	62.03% <ø> (+0.02%)	⬆️

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