kernel: Add progress method to notifications

Summary:
This commit is part of the libbitcoinkernel project and seeks to remove
the ChainstateManager's and, more generally, the kernel library's
dependency on interface_ui with options methods in this and the
following few commits. By removing interface_ui from the kernel library,
its dependency on boost is reduced to just boost::multi_index.

This is a partial backport of core#27636
https://github.com/bitcoin/bitcoin/pull/27636/commits/4452707edec91c7d7991f486dd41ef3edb4f7fbf
Depends on D16205

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16206