Root folder creation (#2)

This PR contains the work done to create the root folder of a new project when executing the _colibri_ executable. In addition, some other work has been done:

* added the `ArgumentParser` package dependency to the package;
* implemented the `FileService` service in the _library_ target;
* implemented the `CreateRootFolderTask` task in the _library_ target;
* removed some unnecessary comments and boilerplate code;

Reviewed-on: #2
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

Sources/Library/Extensions/URL+Inits.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+extension URL {
+    
+    // MARK: Initialisers
+    
+    init(at filePath: String) {
+        if #available(macOS 13.0, *) {
+            self = URL(filePath: filePath)
+        } else {
+            self = URL(fileURLWithPath: filePath)
+        }
+    }
+    
+}