Simplify changelog

changelog format is annoying, we need to simplify that, client specific columns are unused, also would be nice if we can have a way for this to not conflict between branches, using https://github.com/OffchainLabs/unclog could help there

Start by reviewing the repository's current changelog format and how branches produce conflicting changes. Assess whether the proposed unclog workflow addresses the unused client-specific columns and branch conflicts. Done means a simpler format is defined and a conflict-resistant workflow is documented or adopted.

Written by the indexing model from the issue text.