feat(gnokey): add querying realm balances

[leohhhn]

Description

Closes: #2469

This PR adds code to the handler in gnokey that extends the bank/balances functionality to allow users to fetch the balance of a realm given its pkgpath, ie bank/balances/gno.land/r/demo/wugnot.

Initially I wanted to implement this functionality in the handler for tm2/sdk/bank, but in order to not introduce more tm2<>gno dependencies, I did it in the gnokey query handler. Then, I realized that that handler is also under tm2, in tm2/pkg/crypto/keys/client/query.go :/

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.01%. Comparing base (95115c0) to head (1b17797).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2470      +/-   ##
==========================================
- Coverage   55.02%   55.01%   -0.01%     
==========================================
  Files         595      595              
  Lines       79662    79661       -1     
==========================================
- Hits        43832    43826       -6     
- Misses      32514    32517       +3     
- Partials     3316     3318       +2     

Flag	Coverage Δ
contribs/gnodev	25.65% <ø> (-0.35%)	⬇️
contribs/gnofaucet	14.46% <ø> (ø)
contribs/gnomd	0.00% <ø> (ø)
gno.land	64.24% <ø> (ø)

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[moul]

good idea, but it should be implemented from sdk/vm.Handlers, not from keys/client.

[leohhhn]

@moul

The issue is the following; you can find only the VM queries in gno.land/pkg/sdk/vm:

QueryPackage = "package"
QueryStore   = "store"
QueryRender  = "qrender"
QueryFuncs   = "qfuncs"
QueryEval    = "qeval"
QueryFile    = "qfile"

On the other hand, bank/balances is querying the banker which lives separately, in tm2/sdk/bank.

I did this change in keys/client instead of in tm2/sdk/bank because I thought we wanted to keep tm2 & the banker agnostic to the VM they're communicating with. Let me know if I'm wrong on this.

With my implementation, gnokey would do the argument parsing locally and and the query would not change on the side of the chain.

[moul]

The issue is the following; you can find only the VM queries in gno.land/pkg/sdk/vm:

Yes, that's exactly where I recommend implementing it: directly from this package, instead of from keys/client.

[moul]

tm2 should not import gnovm/ or gno.land/.