Add ability to revert files to previous versions

[jelveh]

Puter currently tracks file versions automatically on write, with version history stored in the database. However, there is no user-facing API to restore files to previous versions.

What is needed:

• API methods/endpoints to manage versions (listing is already implemented)
• Corresponding Puter.js methods to work with versions.
• Corresponding GUI functionality to work with versions. File 'properties' window should be a good place to do this since it already shows versions.