API refactor: App connectors transaction requirements

[0xGabi]

This issue is to discuss and outline the scope of changes we may need to do to allow the app connector to add more details when sending transactions.

• E.g. Finance and Agreement need token pre-approvals, and it would be easier if those connectors held logic to calculate these

Brett's comment on the subject:

It's becoming clearer now, especially with Agreements and Disputable Voting, that app actions will have more context about the periphery transactions related to an action.

For example, in order to start a disputable vote (called directly or at the beginning of a transaction path), users will have to include one (or two) approval pre-transactions. And for the Agreement, a challenger could have up to four pre-transactions related to token approvals before they actually submit the transaction that starts the challenge.

Given this, I've started leaning more and more on allowing app connectors to include more logic on actions they expose, rather than directly mirroring organization#appIntent().

An alternative to this is providing a standard for app connectors to "hook" into an appIntent() call (e.g. "if I'm included in the forwarding chain, add a transaction"), but this would also force us to configure the app connectors in the main connect() export.