feat!: MaxBorrow query and modify MaxWithdraw to return all denoms

[toteki]

Description

In addition to the existing historacle-enabled MaxWithdraw query, this PR implements the following:

• MaxBorrow

In addition, the Denom field in those queries is now optional, and they return sdk.Coins instead of sdk.Coin. If denom is not specified, calculates max borrow/withdraw for ALL registered tokens.

See proto file for query urls and data types.

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[codecov-commenter]

Codecov Report

Merging #1683 (dd08df6) into main (13745da) will increase coverage by 0.15%.
The diff coverage is 61.96%.

@@            Coverage Diff             @@
##             main    #1683      +/-   ##
==========================================
+ Coverage   57.82%   57.97%   +0.15%     
==========================================
  Files          73       73              
  Lines        7589     7821     +232     
==========================================
+ Hits         4388     4534     +146     
- Misses       2858     2934      +76     
- Partials      343      353      +10     

Impacted Files	Coverage Δ
x/leverage/types/query.pb.gw.go	0.00% <0.00%> (ø)
x/leverage/keeper/limits.go	50.00% <51.61%> (+6.98%)	⬆️
x/leverage/keeper/oracle.go	62.93% <62.50%> (-0.04%)	⬇️
x/leverage/keeper/grpc_query.go	64.84% <72.60%> (+2.29%)	⬆️
x/leverage/client/tests/tests.go	100.00% <100.00%> (ø)

[robert-zaremba]

• Let's simplify and merge All* queries by making the denom optional and always returning a list.
• let's write at least one simple test for the Query RPC.

[toteki]

Merged queries and added basic tests.

Note that PR is now proto-breaking (only for the MaxWithdraw query and response)

[robert-zaremba]

preapproving. As noted in the comment, let's remove the optional flag. According to the proto documentation it doesn't change anything, but makes the implementation a bit more obscure.