Add fee-bump to example-cli example crate

[sjeohp]

Description

Opening for feedback.

This adds a run_bump_cmd to example_cli and tweaks nursery/coin_select/src/coin_selector.rs to allow required utxos.

Notes to the reviewers

Changelog notice

Checklists

All Submissions:

• [ *] I've signed all my commits
• [ ] I followed the contribution guidelines
• [ ] I ran cargo fmt and cargo clippy before committing

New Features:

• [ ] I've added tests for the new feature
• [ ] I've added docs for the new feature

Bugfixes:

• [ ] This pull request breaks the existing API
• [ ] I've added tests to reproduce the issue which are now passing
• [ ] I'm linking the issue being fixed by this PR

[notmandatory]

I put this in the beta.0 milestone since it's only changing example code.