Move processor/subprocessor logic from remote-collateral to support swapping on ass swap API

[mpetrunic]

Summary

Move the processor / subprocessor logic out of remote-collateral so it can support swapping via the ass swap API.

Motivation

The processor/subprocessor logic currently lives in the remote-collateral flow. To support swaps on the ass swap API, this logic needs to be moved here so it can be used by repayment

Scope

• Extract processor/subprocessor logic from remote-collateral.
• Adapt it to support swapping through the ass swap API.

Parent: sprintertech/sprinter-api#1161