Feature/picker

[mhusnainnnaseer786]

Description

This pr will add Picker component in React native paper.

Screenshots (if appropriate):

Types of changes

• 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 change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[mhusnainnnaseer786]

Sir @artalat ,
If I render children in picker with mode="dialog" | "menu" then it through an error . Because children are of PickerItem type which needs Picker as their Parent and in our case parent is dailog or menu.