Update mimetype icons

[AndyScherzinger]

based on nextcloud/files-clients#46 (comment) and nextcloud/server#44340

• Text file: article
• Document: description in #49abea
• Spreadsheet: file-table-box in #9abd4e
• Presentation: file-presentation-box in #f0965f
• Diagram: drawing-box in #b39114
• PDF: picture-as-pdf
• Image: image
• Video: movie

[tobiasKaminsky]

@allexzander @claucambra do we use them somewhere?
I assume that we use OS default ones within Windows Explorer / Finder.
And in activity stream we receive the icons from server, right?

[allexzander]

@tobiasKaminsky

We are receiving from the server for activities (https://github.com/nextcloud/desktop/blob/master/src/gui/tray/activitydata.cpp#L184) and for VFS we also receive from the server via file preview, but yes, in the Explorer/Finder we use OS default, and I am not sure if it will be possible to replace OS default ones with custom ones (lots of work but the investigation is needed first), yet, on Windows, I assume this will break most user's expectations if Nextcloud will totally replace the default icons that are displayed by other software.

I would be glad to have a concrete example with a screenshot of where we need to replace them in the desktop client, for me to be able to have a better idea ad a more precise answer.

[AndyScherzinger]

To be closed with "unplanned" than because there is no case to implement them except for the scenarios where this already happens being shipped by the server 👍