Remove modifications that may be revertable

[rootulp]

Context

While updating the README to describe the rationale for this fork, I noticed a few divergences between this repo and upstream cosmos/cosmos-sdk that I think may be revertable.

Proposal

1. Investigate these modifications and determine if they are revertable or can be moved to celestia-app:

   cosmos-sdk/README.md

   Lines 26 to 34 in bc89c06

   	Modifications that may be revertable:
   	1. Override the default keyringBackend from `os` to `test`. Maybe move to celestia-app
   	1. Increase `DefaultGasLimit` from 200000 to 210000.
   	1. Remove `Evidence` from grpc/tmservice/types.pb.go.
   	1. Override simapp test helpers `DefaultGenTxGas` from 10000000 to 2600000.
   	1. Disable staticcheck golangci lint after fixing lint errors.
   	1. In auth/tx/query.go disable the prove flag when querying transactions
   	1. In server/util.go remove `conf.Consensus.TimeoutCommit = 5 * time.Second`

2. Revert / move to celestia-app
3. Remove the list from the README