[Fixes #763] Introduced labelled checkboxes

[michalfita]

Purpose

To address #763 and improve overall UX of using Checkbox in the application.

Scope

• The implementation
• Examples

To do

• Add label for showing selection over whole Checkbox
• Create grouping for MultiChoice to make application logic easier
• Example combining Checkbox and RadioButton

Notes

Commits bring changes incrementally, so I suggest reviewing them one by one and consider rejections based on changes in them as maybe not all PR would need to be rejected at once.

For now I do draft for first impression where I'm heading. I'm trying to not break original API, however, some alignment with RadioButton in future would do good.