Update MsgUpdateChainInfo to only provide one chain

[lumtis]

Describe the Issue

MsgUpdateChainInfo currently requires providing the entire structureand replace the entire structure in the store. This current workflow can have a risk or removing or changing existing chains

We should update the message to allow only providing a single chain and prevent making mistakes

In addition, we need to add a new message to remove an existing chain

Tasks

Preview Give feedback

1. Add new admin authorization MsgRemoveChainInfo on Testnet
2. Add new admin authorization MsgRemoveChainInfo on Mainnet