[SC] Implement custom fees through the precompiled contract

[darius279]

As a user, I want that the custom fees could by managed through the SC.

Context

Currently, there is a missing precompiled implementation that avoid us to use the custom fees through our smart contacts and for that reason we have not role account management for that feature.

Once Hedera add this feature into the precompiled we should add this functionality to our main code.

hashgraph/hedera-smart-contracts#607

Description

During the stablecoin creation, when the CLI and the UI ask for how will manage the custom fees, we should add as default option "The SmartContract" and also keep the other ones like Current user key and Other key.

This should works in the same way like KYC management.

Acceptance criteria

• When I am creating a stablecoin, I can choose SmartContract as custom fees keys.
• Given a token where the Smart contract key is the custom fees key, I am able to add and remove custom fees.

[darius279]

Missing precompiled implementation