Add fileStorageUploadField and fileUploadField Components to UI Samples

[AmirShelli]

This pull request introduces two new components to the UI samples: fileStorageUploadField and fileUploadField. Added their description and its Russian localization.

[AmirShelli]

Implemented the requested changes.

[honest-niceman]

@knstvk please take a look, LGTM

[knstvk]

@AmirShelli

• please explain in the description:
  • how to use the example: what file types and sizes are accepted.
  • the fact that the example of fileStorageUploadField does not actually saves the file in the storage. Add a comment to the code explaining that it's just a demo code and should not be used in production.
• rename the section to File Upload Fields

Also, how the drop zone is supposed to work? When I drag-drop a file to the component from macOS Finder, the file is downloaded instead of uploaded.

[AmirShelli]

@knstvk Implemented the requested changes:

• Adjusted the description accordingly
• Included instructions on how to use the drag-and-drop zone
• Changed the section name to "File Upload Fields"