[webapp] Files/attachments are not encrypted

[aguinetqb]

Ticket to track ideas/advances on that known limitation.

Looks like using a combination of https://developers.mattermost.com/integrate/plugins/webapp/reference/#registerFilesWillUploadHook & https://developers.mattermost.com/integrate/plugins/webapp/reference/#registerFilesWillUploadHook could do the job. We will still have some limitations. For instance, Mattermost has an image preview feature which resize the image into a smaller one server-side, which obviously can't be done in our case!

[feha]

@aguinetqb what's the current status for this? And is it really only for the [webapp]? I were using the desktop version when uploading a test attachment, and it wasn't encrypted either.