Make graph metrics public

[zslade]

Type of PR

• BUG
• FEAT
• MAINT
• DOC

Is your Pull Request linked to an existing Issue or Pull Request?

Related PRs:

• Original metrics PR (cluster size and density): Cluster metrics #1677
• Add node degree + cluster centralisation : Cluster metrics - node degree + cluster centralisation #1806
• Add 'is bridge': Implement is_bridge edge metric #1894
• Tweaks and fixes: Fixes to _compute_cluster_metrics #1763, return data class instead of dictionary #1887, compute_graph_metrics - compute what we can without igraph #1982, Change file name to reflect graph naming conventions #2015

Give a brief description for the solution you have provided

This PR signals the end of the first development round of the graph metrics functionality and makes it public 🙌

PR Checklist

• Added documentation for changes
• Added feature to example notebooks or tutorial (if appropriate)
• Added tests (if appropriate)
• Updated CHANGELOG.md (if appropriate)
• Made changes based off the latest version of Splink
• Run the linter

[ADBond]

Looks great, just one small change to the changelog.

Thanks for hunting down all the relevant PRs, very handy for reference!

[RobinL]

This is great! Very exciting!