types: Add call options to submit transaction to simplify API

[nickcorin]

This is just a draft proposal intended to facilitate a conversation around API simplification across chains.

For example, most transctions submitted through the ChainWriter will use a zero value parameter. The implications of this is that most products will be passing in nil. We may as well try and simplify the call for the majority of use cases. while still providing the functionality for those who want to use it.

I've made options for TxMeta and the TransactionID. This is mostly for PoC sake, and is not a proposal to make those specific params optional.