Add pruning of generations call messages

[ross-weir]

Description

Adds 2 pruning generation call messages:

1. Admin based that can prune a list of credential ids of anyone. Uses the chain state admin (for backwards compat) - allows state clean-up
2. User based that can prune their own credential id corresponding to the address that sends it - allows fixing borked generations (IIRC u64::max can cause a break)

• I have updated CHANGELOG.md with a new entry if my PR makes any breaking changes or fixes a bug. If my PR removes a feature or changes its behavior, I provide help for users on how to migrate to the new behavior.
• I have carefully reviewed all my Cargo.toml changes before opening the PRs. (Are all new dependencies necessary? Is any module dependency leaked into the full-node (hint: it shouldn't)?)

Linked Issues

• Fixes # (issue, if applicable)
• Related to # (issue)

Testing

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