Add modal focus trap feature

[sebnitu]

Problem

There are a few outstanding accessibility issues with the current modal script.

Solution

This PR improve the modal component by introducing a focus trap feature. This ensures that while a modal is open, it's not possible to access the rest of the page using tab focus. In addition to this, a new enable and disable state management has been along with a main selector option which will make primary content areas within a page inaccessible while a modal is active. Lastly, to better improve the management of modals, a new move modal option and api was added to move all modals in a document to a specific location. This prevents a modal from inheriting the inaccessible state if it's originally within the main content area. The new modal behavior pattern is as follows:

1. When a modal is opened, focus is moved to the dialog or an element inside.
2. Modals provide standard methods for the user to close such as using the esc key or clicking outside the dialog.
3. While the modal is active, contents obscured by the modal are inaccessible to all users.
4. When a modal is closed, focus is returned to the initial trigger element that activated the dialog.