Make certain Bezier function parameters optional and other refactors (#713)

* Make certain parameters optional

* Use builder pattern for project function's optional parameters

* Address comments posted in bezier-math-lib discord channel

* Minor changes to text

* Address PR comments

* Fix index.html

* Nit

* Replace builder pattern with simple struct

* Move constants to a separate file

Co-authored-by: Keavon Chambers <keavon@keavon.com>

bezier-rs/docs/interactive-docs/src/utils/types.ts

@@ -12,6 +12,7 @@ export type SliderOption = {
 	step: number;
 	default: number;
 	variable: string;
+	unit?: string;
 };
 
 export type TemplateOption = {