Add feature to display image instead of file path and document preview feature

[ProMeX04]

This pull request introduces several changes to improve clipboard handling, enhance code maintainability, and update configuration defaults. The most significant updates include better handling of image files in the clipboard, modularizing clipboard-related logic into extensions, and updating default application settings.

Clipboard Enhancements:

• Added support for additional image types (.jpeg, .heic) in the supportedTypes set and introduced logic to handle image file URLs, ensuring that both file URLs and image data are processed appropriately. (Maccy/Clipboard.swift, [1] [2] [3] [4] [5]
• Modularized image file handling into a new extension Clipboard+ImageHandling.swift, improving code organization. (Maccy/Extensions/Clipboard+ImageHandling.swift, Maccy/Extensions/Clipboard+ImageHandling.swiftR1-R59)

Code Refactoring:

• Moved logic for clipboard validation, copy-paste operations, and formatting removal into separate extensions (Clipboard+Validation.swift, Clipboard+Operations.swift), enhancing readability and maintainability. (Maccy/Extensions/Clipboard+Validation.swift, [1]; Maccy/Extensions/Clipboard+Operations.swift, [2]
• Made several properties and methods in Clipboard internal to improve accessibility for extensions. (Maccy/Clipboard.swift, Maccy/Clipboard.swiftR22-R43)

Configuration Updates:

• Updated .swiftlint.yml to include file length warnings and errors, ensuring better adherence to coding standards. (.swiftlint.yml, .swiftlint.ymlR7-R9)
• Adjusted default application settings, such as reducing the default window size and adding options for showing delete and preview buttons. (Maccy/Extensions/Defaults.Keys+Names.swift, [1] [2]

Minor Code Improvements:

• Improved thread safety and memory management by using [weak self] in asynchronous code. (Maccy/AppDelegate.swift, Maccy/AppDelegate.swiftL163-R164)
• Simplified and reformatted code for readability, such as in the credits property. (Maccy/About.swift, Maccy/About.swiftL26-R29)

[weisJ]

Your PR introduces lots of superfluous formatting changes to almost all files. You don’t have to close and reopen the PR, just amend the commits and force push.

[weisJ]

This is still the case. Please don't change the SwiftLint config (which is likely the culprit here).