[refactor] Minimize use of JS DOM API in the Tooltip component

[suzubara]

The Tooltip component (added in #871) uses a lot of the USWDS vanilla JS source code. Since we're using React to build components, we can replace most (if not all) of that with React features, such as useState, useRef, useEffect, in order to follow React best practices and write declarative code instead of imperative.

Suggested changes:

• Replace the setPositionClass and positionXYZ functions with state values for storing the position and style attributes (which can be updated when the Tooltip is opened)
• Apply custom classes to the trigger and wrapper elements in the Tooltip component (instead of inside the useTooltip hook)