Feature: Added support for previewing Office files

[gave92]

Resolved / Related Issues

• Were these changes approved in an issue or discussion with the project maintainers? In order to prevent extra work, feature requests and changes to the codebase must be approved before the pull request will be reviewed. This prevents extra work for the contributors and maintainers.
• Closes Feature: Add Preview for Office files - Word, Excel #4041
• Closes PDF be vertical rather then horizontal scrolled in preview section #13044
• Closes Choice of preview handlers #5582
• Closes Bug: PDF preview pages are very blurry at low scaling #5117

Status

• The preview renders in the correct z-order
• The preview accepts mouse/keyboard input (hackish)
• The preview follows system theme, not Files setting (light/dark)
• ContentExternalOutputLink requires experimental version of WinAppSdk

Validation
How did you test these changes?

• Did you build the app and test your changes?

Screenshots (optional)

[mdtauk]

Is there any way to contain these Win32 controls better to ensure a good and consistent Preview Pane design?

[yaira2]

@ahmed605 fyi

[yaira2]

@gave92 is there supposed to be a way to select text when previewing a Word document?

[yaira2]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[gave92]

Works nicely with PowerToys previews :)

Files.-.Files.2023-08-20.12-30-02.mp4

[yaira2]

@gave92 fantastic!

[yaira2]

LGTM