WizardShell, navigation and skeleton components

[pasanchMSFT]

Summary of changes 🔍

Added WizardShell component to allow users to navigate to all 4 screens planned:

• Data source connector
• Twin verification
• Relationship builder
• Save

*Also added the skeleton component for each one of those screens/steps.

Modified StepperWizard component to allow navigation to be controlled by context, added this component to the Legion folder because more changes are planned for it.

Testing 🧪

Open Storybook and take a look at WizardShell stories to see how navigation with stepper component works.

Checklist ✔️

• [ ] Linked associated issue (if present)
• [ ] Added relevant labels
• [ ] Requested developer reviews
• [ ] Request UI review from design / PM
• [ ] Verify all code checks are passing