Cleanup devhub images (#6662)

* Remove unused images from hub/images

Delete 22 orphaned images (logos and screenshots for old JS framework, Android Studio, and other docs) that are no longer referenced anywhere in the repo.

Co-authored-by: Copilot <[email protected]>

* Move PowerToys images to hub/powertoys/images

Move 134 PowerToys-only images out of the shared hub/images folder into hub/powertoys/images (preserving the command-palette, powertoys-awake, and powertoys-workspaces subfolders), and update all image references in PowerToys docs accordingly.

Co-authored-by: Copilot <[email protected]>

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Co-authored-by: Copilot <[email protected]>

Author: niels9001