[time-picker] introduced a11y

[msereniti]

Made time-picker accessible for Screen readers.

Description

I have hid combobox popups for screen readers and added several necessary labels. Also I have removed weird searching for sibling inputs to focus it and replaced with predictable refs.

How has this been tested?

I have added VO tests

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.