Keyboard navigation and selection for WCAG

[CharlesVanek]

When navigating with keyboard only, pressing Enter on the Notes ## navigation should put cursor focus into the list of ## notes. From there the user should be able to arrow up/down through the Notes and press Enter to be taken to the Note's Pane for editing.

To Reproduce
Steps to reproduce the behavior:

1. Open Stndard Notes on Windows; Tab to navigation "Notes ##" where ## is the number of notes you have
2. Press Enter on "Notes ##"

Expected behavior
Cursor positioning to move to the list of Notes (this does not occur) and the user should be able to navigate the list of Notes with up/down arrows.

Desktop (please complete the following information):

• OS: Windows 11
• Browser : N/A
• Version: standard-notes-3.195.1-win-x64

Additional context
This is critical for WCAG compliance to navigate the Standard Notes application using screen readers for for people who can't use a pointing device and rely upon keyboard navigation.
In addition it's beneficial for productivity of all users.