Logging changes

- Adds `Logging` protocol
- Moves to Swift-style `OSLog` usage

os_log to Logger

os_log audit

Replacment of os.log with Logging

Mac/Scriptability/AppDelegate+Scriptability.swift

@@ -55,7 +55,7 @@ extension AppDelegate : AppDelegateAppleEvents {
 			
 			if let themeURL = URL(string: themeURLString) {
 				let request = URLRequest(url: themeURL)
-				let task = URLSession.shared.downloadTask(with: request) { location, response, error in
+				let task = URLSession.shared.downloadTask(with: request) { [weak self] location, response, error in
 					guard let location = location else {
 						return
 					}
@@ -64,6 +64,7 @@ extension AppDelegate : AppDelegateAppleEvents {
 						try ArticleThemeDownloader.shared.handleFile(at: location)
 					} catch {
 						NotificationCenter.default.post(name: .didFailToImportThemeWithError, object: nil, userInfo: ["error": error])
+						self?.logger.error("Failed to import theme: \(error.localizedDescription, privacy: .public)")
 					}
 				}
 				task.resume()