MVP refactorings & cleanups

[klummy]

These are tasks that don't affect functionality but are improve the user and development experience. Also, meant as a way to track pending

• Complete migration from class components to hook based components where possible
• The QueryPane component is becoming too complicated and will likely become harder to maintain. Clean it up by splitting where necessary and rethink logic.
• Modify the remove NotificationItem effect to trigger when the notification is in view, not when it appears (perhaps using IntersectionObserver?)
• Allow for scrolling the notification list when the items overflow the screen.
• Don't dismiss/remove the notification when it's hovered on for a better usability experience
• Consider looking for a better alternative to replacing items in arrays (used for update* tasks in reducers)

Pending test tasks:

• Test Redux action creators and reducers
• Test all components especially those that have conditional rendering within them
• Test effects and services