feat(stepper): allow component to stepper label

[HitomiWin]

Describe your changes

Add possibility to use custom component as a stepper label

Issue ticket number and link

• Fixes Stepper: component as a stepper label #217

Checklist before requesting a review

• I have performed a self-review of my own code
• I have verified that the code builds perfectly fine on my local system
• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have verified that my code follows the style already available in the repository
• I have made corresponding changes to the documentation