Player accessibility improvements

[clpetersonucf]

• Tab index is overridden with discrete values > 1, which should be reverted to a default tab flow
• Many DOM elements are not representative of their actual role, or do not have appropriate roles applied
• Focusable element navigation and flow is inconsistent with ARIA standards
• Not all focusable elements have a :focus style applied
• Improvements should be made to clue selection and board navigation