[Milestone Tracker] Implementation of Manual CPFP for Revault Managers

[Zshan0]

Corresponding to revault/revaultd#411, this issue is to update the progress that will be made on the implementation of manual CPFP command for managers on the revault-gui side. The API on revaultd's side has been fixed allowing the work on revault-gui to start. The implementation can be broken down as follows:

• Implementation of the revaultd caller on revault-gui
• Tests for the caller
• UI addition that will trigger manual CPFP
• Tests for the UI

Due to the assumption that revaultd API works independently of the GUI, it can be assumed that proper functionality of both revaultd and revault-gui sides of manual CPFP API implies that the overall API works well too.