fix!: remove grpc query routing through tendermint

[tac0turtle]

Description

Revert routing queries through tendermint.

The reason this change was made is because of this error:

fatal error: concurrent map read and map write

The person who identified this error submitted these steps to reproduce

User sends a query with grpc
Tendermint Commit new blocks and tries to Commit IAVL (which causing IAVL versions map to change)
At the same time query tries to read from the same map (iavl.(*MutableTree).VersionExists) to check if requested version is exists
Node exits with fatal error: concurrent map read and map write

With the recent changes to IAVL submitted by terra (cc @YunSuk-Yeo) the reason for why we need to route through tendermint is no longer present. We should revert it when 0.17.1 of IAVL is cut, which will be later today.

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[codecov]

Codecov Report

Merging #10045 (35b641b) into master (1e2ef52) will increase coverage by 0.00%.
The diff coverage is 24.52%.

❗ Current head 35b641b differs from pull request most recent head 21d5424. Consider uploading reports for the commit 21d5424 to get more accurate results

@@           Coverage Diff           @@
##           master   #10045   +/-   ##
=======================================
  Coverage   63.66%   63.66%           
=======================================
  Files         573      573           
  Lines       53816    53795   -21     
=======================================
- Hits        34260    34251    -9     
+ Misses      17607    17596   -11     
+ Partials     1949     1948    -1     

Impacted Files	Coverage Δ
baseapp/grpcserver.go	1.75% <0.00%> (+0.03%)	⬆️
client/grpc_query.go	36.50% <44.00%> (-0.48%)	⬇️
baseapp/grpcrouter.go	85.93% <100.00%> (+6.20%)	⬆️
server/grpc/server.go	64.51% <100.00%> (ø)
crypto/keys/internal/ecdsa/privkey.go	82.45% <0.00%> (-1.76%)	⬇️
x/bank/migrations/v045/keys.go
x/bank/migrations/v045/store.go
x/bank/migrations/v044/store.go	75.00% <0.00%> (ø)
... and 1 more

[adizere]

+1 for this PR!

This fix may prove useful to relayer operators. Some relayers (Hermes in particular) tend to put a lot of pressure on the RPC+GRPC endpoints of full nodes, making it necessary to use relatively beefy machines. (As a side note, there's also some anecdotal evidence that the gRPC endpoint is not very reliable, e.g., informalsystems/hermes#1220 but unclear if related to routing via tendermint.)

Any estimate on when this will land into SDK line(s)?

[alexanderbez]

@marbar3778 can you please address @ValarDragon's comments before merging?

[ethanfrey]

Until know, the gRPC server just called into Tendermint RPC, which then called the ABCI app to make the query.

In CosmJS, we figured this was extra overhead and just called Tendermint RPC directly with those queries, and this worked great. (Especially as the gRPC server was quite buggy until March 2021 or so).

This PR now means there are two different paths - gRPC -> ABCI and Tendermint RPC -> ABCI, which different characteristics? Can you explain what the difference between these two is after this PR? (eg. will we have trouble to keep calling Tendermint RPC directly?)

[tac0turtle]

This PR now means there are two different paths - gRPC -> ABCI and Tendermint RPC -> ABCI, which different characteristics? Can you explain what the difference between these two is after this PR?

This PR reverts routing grpc queries through tendermint. Now it should go directly to the store instead of tendermint. Ideally, apps are queryable without tendermint as this can block other parts of tendermint from starting