Support omni-bridge token wrapping

[BonelessImpl]

We support omni bridge by wrapping its token with the PoA tokens. This PR supports migrating a token from being used as an owned token, vs being used to wrap omni bridge.

The upgrade takes two steps:

1. Mandatory initial contract upgrade, which will add a field that contains the target wrapped token as options

2. After step 1, the token remains as PoA with nothing changes. Once the migration to Omni bridge is done, we set the wrapped token address, which will change the behavior of the smart contract to wrap omni-bridge

[mitinarseny]

Please, remember to add to both: PoA Token & PoA Factory:

impl ControllerUpgradable for Contract {
    #[only(self, owner)]
    fn upgrade(...) -> Promise { /* ... */}
}