Fetch and generate shadow styles

[timbaev]

Generate shadow styles from Figma file!

1. Create local Effect Styles in Figma file
   
2. Configure fugen.yml file, e.g.:

shadowStyles:
  file:
    key: gZ0sNyG5kflJGqa9JvO5lL
    includedNodes:
      - 193%3A2
  destination: FugenDemo/Generated/ShadowStyle.swift
  templateOptions:
    publicAccess: true
    shadowViewTypeName: ShadowView

3. Generate code using CLI:

fugen generate

4. Example usage in code:

@IBOutlet private weak var shadowWiew: FugenShadowView!

shadowWiew.shadowStyle = .card16dpShadow

Available template options:

Key	Type	Default value	Description
styleTypeName	String	ShadowStyle	Style type name
shadowViewTypeName	String	FugenShadowView	Name of generated view to which the shadow style is applied.
colorTypeName	String	UIColor	Color type name. If the target platform is macOS, specify NSColor.
viewTypeName	String	UIView	View type name. If the target platform is macOS, specify NSView.
bezierPathTypeName	String	UIBezierPath	Bezier path type name. If the target platform is macOS, specify NSBezierPath.
publicAccess	Boolean	false	Flag that adds public access modifier to the declarations in the generated file.

[almazrafi]

💪Thanks for the PR!