Add the 'Blend Shapes' and 'Origins to Polyline' nodes; generalize the 'Morph' node to >2 states (#3405)

* New nodes: 'Morph' and 'Multi-Morph'

* Blend Shapes node

* Add the 'Index Points' node

* Fix failing test

node-graph/libraries/no-std-types/src/registry.rs

@@ -19,6 +19,8 @@ pub mod types {
 	pub type Length = f64;
 	/// 0 to 1
 	pub type Fraction = f64;
+	/// Non-negative number broken into whole and fractional parts
+	pub type Progression = f64;
 	/// Signed integer that's actually a float because we don't handle type conversions very well yet
 	pub type SignedInteger = f64;
 	/// Unsigned integer