[network] Add Upstream / Downstream role definitions
[network] Add Upstream / Downstream role definitions

Providing a list of Upstream / Downstream role definitions based on
information about the caller or receiver relative to it.

libra/libra,libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core