Ability to override token-specific egress fees based on destination account

[stephenpdeos]

In our approach to designing a solution for a coin-centric model for specific tokens capable of being bridged between EOS EVM and EOS Native, a requirement was identified that we may wish to adjust egress fees based on the available methods to move tokens off of EOS EVM.

Acceptance Criteria

• There must be a method to manage egress fee values in relation to a given destination account or list of destination accounts. One example may be a list of exchanges directly integrated with EOS EVM and another may be exchanges that support in-line transfers, but are not yet directly integrated with EOS EVM.
• There must be a way to override the default egress fee for the (token symbol, destination EOS account) pair.