Cosmos-sdk: remove the `advanced` gaiacli command and putting all the sub-command at root

[jackzampolin]

Currently the gaiacli has the following command structure:

├── advanced
│   ├── ibc
│   │   ├── relay
│   │   └── transfer
│   ├── rest-server
│   └── tendermint
│       ├── block
│       ├── tx
│       ├── txs
│       └── validator-set

advanced should be removed and ibc, rest-server and tendermint should be moved to top level commands.

[alexanderbez]

Yeah I have to agree here 👍

[nylira]

+1 saves my fingers