Add possibility to prevent month focusing

[qxFisher]

Types of changes

What types of changes does your code introduce?

Put an x in the boxes that apply

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

Description

Added additional Calendar preventFocusOnDateChange prop to prevent any month jumping completely.

Related Issue: #515

[raDiesle]

Can it be that also the new code change will enrich the issue described in linked ticket? Whenever props change on Calendar, and the component rerenders, the view will snap to the focused date, which might be not what the user wants to see, if he already started navigating.