NH-3724 - Added support for notification handlers

[hazzik]

Replaces #363

[hazzik]

/rebase

[autorebase[bot]]

The rebase failed:

Not Found

To rebase manually, run these commands in your terminal:

# Fetch latest updates from GitHub.
git fetch
# Create new working tree.
git worktree add .worktrees/rebase rjperes-NH-3724
# Navigate to the new directory.
cd .worktrees/rebase
# Rebase and resolve the likely conflicts.
git rebase --interactive --autosquash master
# Push the new branch state to GitHub.
git push --force
# Go back to the original working tree.
cd ../..
# Delete the working tree.
git worktree remove .worktrees/rebase