#43: Add DesignKit package

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

DesignKitTests/DesignKitTests.swift

@@ -0,0 +1,8 @@
+import XCTest
+@testable import DesignKit
+
+final class DesignKitTests: XCTestCase {
+    func testExample() throws {
+        XCTAssert(true)
+    }
+}