Support Undelegate and CollectRewards transactions into rosetta config

[renlulu]

Currently, we cannot add Undelegate and CollectRewards into Rosetta config due to:

1. We cannot easily pre-define delegator/validator address, so we don't know this kind of info util run time(after CreateValidator and Delegate happen), so we'll need to figure out how to make rosatte use the same account as delegate transaction for Undelegate.

2. The moment when Undelegate and CollectRewards is happening, the amount is actually 0, which cannot pass Rosetta-cli's check for now.

Related PR including:

harmony-one/harmony#3664

#8