evm: in-process store migrations

[fedekunze]

The EVM module is missing the in-process store migrations.

• https://docs.cosmos.network/master/core/upgrade.html#add-storeupgrades-for-new-modules

[yihuang]

it seems EVM module's storage and parameters didn't change after 0.7.2 release, the only migration needed is adding the feemarket module, but that can be done in the app upgrade handler directly I think.
We should have it a test to confirm though.

[fedekunze]

@yihuang we should still add the command though. Otherwise, the genesis.json is going to be huge because of the contract code and storage. cc @tomtau @thomas-nguy