Make bridge token's metadata on NEAR customizable by the user who deployed the token

[think-in-universe]

Description

We have some cases that the bridge token's NEP141 metadata (e.g. symbol, name, icon, decimals, etc.) needs to be customized when the token is bridged from an ERC20 token ETH.

While set_metadata is only allowed by the bridge token factory, it might be helpful under some circumstances for the account who deployed the token to be able to set metadata.

However, this may bring some confusion or security risks, if attackers try to create mismatched pairs to mislead users.

Please review whether this is possible from frontend and connectors.

[mfornet]

Near-One/rainbow-token-connector#73 will add the functionality to update metadata from a trusted services and Near-One/rainbow-token-connector#71 from trustless parties.