[Setup] Non Apple platforms (#13)

This PR contains the work done to address the issue #12, with regards to provide basic support of non Apple platforms.

To provide further details about the work done:
- [x] flattened the folder structure, especially now that the idea to filter folders based on platform is being discarded;
- [x] implemented precompiler processors to filter out platform-specific source code;
- [x] updated the `Package` file to provide basic support for non-Apple platforms;
- [x] added and also improved some targets to the `Makefile` file to smooth the current development workflows;
- [x] updated the `.gitignore` file with references to the `.vscode` folder and the `.env` file;
- [x] updated the Swift tools version to v5.7.

Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Reviewed-on: #13

Sources/Communications/Classes/MockURLProtocol.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS) || os(macOS) || os(tvOS) || os(watchOS)
 import Foundation
 
 /// This class overrides the `URLProtocol` protocol used by the `URLSession` to handle the loading of protocol-specific URL data so it is possible to mock URL response for testing purposes.
@@ -116,3 +117,4 @@ public struct MockURLResponse {
     }
 
 }
+#endif

Sources/Communications/Use Cases/MakeURLRequestUseCase.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS) || os(macOS) || os(tvOS) || os(watchOS)
 import Foundation
 
 /// This use case generate a url request out of a given endpoint.
@@ -55,3 +56,4 @@ public struct MakeURLRequestUseCase {
     }
 
 }
+#endif

Sources/Coordination/Routers/BaseNavigationRouter.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS)
 import UIKit
 
 /// This is a base class for the `NavigationRouter` concrete router implementations.
@@ -70,3 +71,4 @@ extension BaseNavigationRouter: UINavigationControllerDelegate {
     }
 
 }
+#endif

Sources/Coordination/Routers/ModalNavigationRouter.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS)
 import UIKit
 
 /// This class is responsible for showing view controllers modally, as it is a concrete implementation of the `Router` protocol.
@@ -88,3 +89,4 @@ private extension ModalNavigationRouter {
     }
     
 }
+#endif

Sources/Coordination/Routers/PushNavigationRouter.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS)
 import UIKit
 
 /// This class is responsible for pushing view controllers into a navigation controller, as it is a concrete implementation of the `Router` protocol.
@@ -66,3 +67,4 @@ extension PushNavigationRouter: Router {
     }
     
 }
+#endif

Sources/Coordination/Routers/WindowRouter.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if os(iOS)
 import UIKit
 
 /// This class is responsible for populating the window of an application.
@@ -45,3 +46,4 @@ public class WindowRouter: Router {
     }
     
 }
+#endif

Sources/Persistence/Classes/Fetcher.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if canImport(Combine) && canImport(CoreData)
 import Combine
 import CoreData
 
@@ -167,3 +168,4 @@ public enum Change: Hashable {
     case section(SectionUpdate)
     case object(ObjectUpdate)
 }
+#endif

Sources/Persistence/Protocols/Service.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if canImport(CoreData)
 import CoreData
 
 public protocol Service {
@@ -38,3 +39,4 @@ public protocol Service {
     func save(childContext context: NSManagedObjectContext) throws 
     
 }
+#endif