feat: add initial People Playground mod development kit

extracted_wiki_content/internalReference/environmentcontrolbehaviour.txt

@@ -0,0 +1,26 @@
+URL: https://wiki.studiominus.nl/internalReference/EnvironmentControlBehaviour.html
+Title: People Playground Modding - EnvironmentControlBehaviour
+==================================================
+
+public class EnvironmentControlBehaviour
+Inherits MonoBehaviour
+Behaviour that controls a UI element in the environment settings panel
+Fields
+public TextMeshProUGUI Label
+Reference to the label mesh
+
+public HasTooltipBehaviour Tooltip
+Reference to the HasTooltipBehaviour determining the tooltip for this control
+
+public UnityEngine.UI.Toggle Toggle
+[Space]
+Reference to the possible toggle element
+
+public UnityEngine.UI.Button Button
+Reference to the possible button element
+
+public TMP_InputField NumberInput
+Reference to the possible number / input element
+
+public TMP_InputField SecondaryInput
+Reference to the possible second input element