[TraceQL] Implement structural operators

[mdisibio]

What this PR does:
Implements descendant (>>), child (>), and sibling (~) structural operators in vParquet2. The TraceQL engine now passes new intrinsics to storage so it can load the minimum columns (each operator uses a different set of columns). The Span interface was updated with generic methods DescendantOf(span) that the engine calls, so it is agnostic to how this data is represented in the backend. I.e. we are not exposing the raw left/right/parent integers to the engine. There are pros and cons to this approach, it is more flexible and as we implement TraceQL on other formats (live traces?), I think it will be better. The drawback is it means a very naive algorithm in the engine to detect the relationships O(n * m). If the engine had the integers it could do fancy things like put them in a map or sorted slice. I think for most cases n and m will be small.

Note: My formatter is now gofumpt, so there is a little bit of noise from the fumpting.

Which issue(s) this PR fixes:
Fixes ?? <-- If we have an issue to track structural operators I couldn't find it.

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[joe-elliott]

looks great! obvious asks: changelog and docs for the new traceql features

[github-actions]

The backport to r103 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 branch
git switch --create backport-2625-to-r103 origin/r103
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x ac63a44eb82520d01c42bab70cfab64e4328c3fb
# When the conflicts are resolved, stage and commit the changes
git add . && git cherry-pick --continue

If you have the GitHub CLI installed:

# Create the PR body template
gh pr view 2625 --json body --template 'Backport ac63a44eb82520d01c42bab70cfab64e4328c3fb from #2625{{ "\n\n---\n\n" }}{{ index . "body" }}' > .pr-body.txt
# Push the branch to GitHub and a PR
gh pr create --title "[r103] [TraceQL] Implement structural operators" --body-file .pr-body.txt --label "type/bug" --label "backport" --base r103 --milestone r103 --web

Or, if you don't have the GitHub CLI installed (we recommend you install it!):

# If you don't have the GitHub CLI installed: Push the branch to GitHub and manually create a PR:
git push --set-upstream origin backport-2625-to-r103
# Remove the local backport branch
git switch main
git branch -D backport-2625-to-r103

Unless you've used the GitHub CLI above, now create a pull request where the base branch is r103 and the compare/head branch is backport-2625-to-r103.