Add variable width histogram aggregation

[stevejgordon]

Closes #5400

[stevejgordon]

Failure in 7.6 is a bit odd and I believe unrelated. I can replicate using the exact same seed only. Needs some investigation but not related to this PR.

[Mpdreamz]

LGTM

[github-actions]

The backport to master failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-master master
# Navigate to the new working tree
cd .worktrees/backport-master
# Create a new branch
git switch --create backport-5402-to-master
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick ---mainline 1 d4929938905ceccc462b09fe986516384f54150a
# Push it to GitHub
git push --set-upstream origin backport-5402-to-master
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-master

Then, create a pull request where the base branch is master and the compare/head branch is backport-5402-to-master.