Add Unreal Socket

Adds a matching Unreal skeleton or skeletal mesh socket by copy/pasting values. Ability to save and load socket data using text files for storage.

Values for relative location and relative rotation should be copied from the Unreal socket details directly using the Shift + RMB hotkey combination. This can then be pasted into the Maya script using Control + V. No need to parse the strings.

The added locator will be parent constrained to the parent bone and have its transforms locked and hidden.

Handles Y-axis flip due to Maya to Unreal conversion.