AUI-1351 - Make aui-color-picker accessible

Hi @Robert-Frampton,

Attached is an update https://issues.liferay.com/browse/AUI-1351.

I abstracted my accessibility changes into two separate classes, aui-color-palette-accessibility and aui-hsv-palette-accessibility.  I also wrote new test cases and created two new test files for them.

Please let me know if there are any issues.

Thanks!