[PXCT-1612] Update UNO Q Cloud Connection Documentation

[91volt]

Summary

This PR updates the UNO Q Arduino Cloud tutorial to reflect the new dedicated setup wizard. It transitions the guide from using the generic "Manual Device" flow to the new specific UNO Q option now available in the Arduino Cloud device registration.

What This PR Changes

• Wizard Update: Replaces the "Manual Device" setup instructions with the new dedicated UNO Q wizard flow (Add Device > Manual Setup > UNO Q).
• Documentation Alignment: Updates the introduction and "Goals" section to remove references to the legacy manual setup.
• Streamlined Instructions: Simplifies Step 2 of the "Set up Arduino Cloud" section to reflect how the Cloud now automatically recognizes and prepares the UNO Q.
• Credential Source: Clarifies that DEVICE_ID and SECRET_KEY are now generated via the official board wizard while maintaining the existing instructions for configuring them within the Arduino App Lab "Cloud Brick."

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