[sistent] Add Stepper component to the sistent components page

[dragon-slayer875]

Current Behavior

Layer5 and it's projects use Sistent library to enable easy component reusability among our various projects.
One such component is Stepper.

Ideally, all sistent components are represented on https://layer5.io/projects/sistent/components, so a centralized usage and example documentation can be maintained. This will aid new developers to more quickly jump into contributing to the various projects.
The Stepper component currently needs this representation .

Desired Behavior

Proper documentation for Stepper component similar to Button component on https://layer5.io/projects/sistent/components
The documentation should include:

• Explanation about the various component props and their expected values
• Code examples for the various variants that a component might have (if any).

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