docs: Add v1.4 release notes

[bryanhuhta]

No description provided.

[knylander-grafana]

Thank you for adding release notes.

[github-actions]

The backport to release/v1.4 failed:

Validation Failed: "Could not resolve to a node with the global id of 'T_kwDOAG3Mbc4AczmP'."

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-2991-to-release/v1.4 origin/release/v1.4
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x a05c3f3158cc9a996d7f0811f5b3f1d00da9b20f

When the conflicts are resolved, stage and commit the changes:

git add . && git cherry-pick --continue

If you have the GitHub CLI installed:

# Push the branch to GitHub:
git push --set-upstream origin backport-2991-to-release/v1.4
# Create the PR on GitHub
gh pr create --title "[release/v1.4] docs: Add v1.4 release notes" --body "Backport a05c3f3158cc9a996d7f0811f5b3f1d00da9b20f from #2991" --label "type/docs" --label "backport" --base release/v1.4 --milestone release/v1.4 --web

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

# Push the branch to GitHub:
git push --set-upstream origin backport-2991-to-release/v1.4

# Create a pull request where the `base` branch is `release/v1.4` and the `compare`/`head` branch is `backport-2991-to-release/v1.4`.

# Remove the local backport branch
git switch main
git branch -D backport-2991-to-release/v1.4