[Peek] Add support for preview handlers

[dillydylann]

Summary of the Pull Request

This PR adds support for preview handlers that displays previews from supported applications like Microsoft Office (assuming the user has it installed).

This should also help with:

• Feature: CLI/API integration for Peek #26422 as these previewers uses a standard API (IPreviewHandler) that's built into Windows and gets hosted by file managers like File Explorer and Everything.
• Community Feedback: Removing PT File Previewer in favor of Peek #26726 as File Explorer plans to move away from its preview pane.

PR Checklist

• Closes: [Peek] Support Office files #26210
• Communication: I've discussed this with core contributors already
• Tests: No tests exist
• Localization: No changes made
• Dev docs: No changes needed
• New binaries: No changes made
• Documentation updated: Mention Office in PowerToys Peek MicrosoftDocs/windows-dev-docs#4635

Detailed Description of the Pull Request / Additional comments

Word

Excel

PowerPoint

Visio

Fonts

[crutkas]

🔥🔥🔥 O_O 🔥🔥🔥

[jaimecbernardo]

Wow! This is a great contribution! Thank you so much!

LGTM, too. I'm a bit skeptical of the unsafe use too, but it makes sense here and the code doesn't look bad intentioned.

We've won gcode from our file previewers from this as well.
I love that it's used as a previewer only if Peek doesn't support that file with the other previewers already.
Tested on a computer that has office installed and this is previewing Office files as well, so I'm guessing we can "check" those as well.

Great contribution, once again! 😄