OOP implementation and improve preferences UX

[thanhph111]

Proposed changes

This pull request proposes an OOP approach to the clipboard implementation, which is better for maintenance and development. These changes also aim to improve user experience on the add-on preferences. Details:

• [x] Reorganize code to specialized modules follow Separation of concerns design : preferences.py (add-on preferences, menu UI, keymaps) and operators.py (operator classes only). __init__.py now contains only metadata (7dc3cc54b399629b85b5cc5b042bb71b6c6d05a9).
• [x] Handle platform operations related to clipboards with following classes which are concreted classes of Clipboard class (support by a list of classes described in dd9c4940b2e8b72eb6c25c92efbf27d76eea7bf0).
  • [x] WindowsClipboard (fdfd421fae36e05bca9178d9b6712d190133fe10).
  • [x] LinuxClipboard (dd9c4940b2e8b72eb6c25c92efbf27d76eea7bf0).
  • [x] DarwinClipboard (001e5b8c134e2815257ff26ecc6bf6a7fc4c30aa, 5c0e789e7bd270c2e765a67e93d69f22c78e445a).
• [x] Rewrite all the operator to perform those classes, reduce duplicate code, better report and better context selection.
• [x] Images should be saved in Blender temporary folder (will be deleted when closing session) if .blend file is not available. This option will free user from specifying a default directory. However, we should allow users to overwrite this directory. The new preferences below (2a99d8cee1bfd5cfea8855b931a88f2288eb3503) added:
  • An option to use another directory for images instead of the temporary directory, including another option to force use it.
  • An option to use subdirectory in the .blend file path.
  • An option to disable debug message.

Old preferences	New preferences

• [x] Discuss about the idea: moving scattered images to .blend file folder when saving. (out of the PR scope)

Further comments

• Windows operations are still very slow. I think it's because the current PowerShell approach depends on too much operations before touching Windows API.
• When rewrite module linux.py, fix an issue make Linux clipboard cannot copy an JPG image (or other types except PNG) (dd9c4940b2e8b72eb6c25c92efbf27d76eea7bf0).

[thanhph111]

@williamchange I am implementing the OOP version of macOS clipboard based on your code, but don't have any knowledge to do the test. Can you help me with this?

[williamchange]

I just checked it out, fixed a couple of issues and opened a PR for it. But there's still some other issues.

[thanhph111]

@Yeetus3141 I suppose we did a good refactoring here, most changes are under the hood but it will help us a lot in the future. We also have a new preferences menu which saves users from having to specify a saving directory if they don't care. About the feature that moves scattered pasted images into .blend file directory when users save file, I think we should save for another PR. Is there any changes you think we should add to this?

[b-init]

Just tried the new build. Seems to be great! Awesome work you guys. And yep the feature of moving scattered images would be good as another PR. And I'll be working on integrating the Video Editor features into the new structure, with possible additions. Unless you've been progressing on it already?

[thanhph111]

Yeah, don't worry, I plan to implement right after merging this and will request your review then.