CMCL-1581: Add Recenter Target option to PanTilt

[glabute]

Purpose of this PR

Added "Recenter Target" feature to PanTilt, because it was available in CM2 POV and missing in CM3. Reported on forums: https://forum.unity.com/threads/cm3-pan-tilt-w-tracking-target-reference-frame-causes-spinning-camera.1583394/#post-9792165

Testing status

• [ ] Added an automated test
• [ ] Passed all automated tests
• [x] Manually tested

Documentation status

• [x] Updated CHANGELOG
• [ ] Updated README (if applicable)
• [x] Commented all public classes, properties, and methods
• [x] Updated user documentation

Technical risk

low

[glabute]

I think API additions are fine