[storage] impl conversions from/to prost proto and GetStartupInfoResponse
[storage] impl conversions from/to prost proto and GetStartupInfoResponse

Closes: #1212
Approved by: mimoo

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