#43: Add DesignKit package

* Begin implementing DesignKit package.
* Use element-design-tokens repo.
* Rename Fonts to align with Colours.

Package.swift

@@ -0,0 +1,27 @@
+// swift-tools-version: 5.6
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "DesignKit",
+    platforms: [.iOS(.v14)],
+    products: [
+        .library(name: "DesignKit", targets: ["DesignKit"])
+    ],
+    dependencies: [
+        .package(url: "https://github.com/vector-im/element-design-tokens.git", branch: "main"),
+        .package(url: "https://github.com/siteline/SwiftUI-Introspect.git", .upToNextMajor(from: "0.1.4"))
+    ],
+    targets: [
+        .target(name: "DesignKit",
+                dependencies: [
+                    .product(name: "DesignTokens", package: "element-design-tokens"),
+                    .product(name: "Introspect", package: "SwiftUI-Introspect")
+                ],
+                path: "DesignKit"),
+        .testTarget(name: "DesignKitTests",
+                    dependencies: ["DesignKit"],
+                    path: "DesignKitTests")
+    ]
+)