add more and fix office mimetypes, migrate wrong mimetypes

Forward port of https://github.com/owncloud/core/pull/7767, the icons are left out because master already has new ones. @icewind1991 @MorrisJobke please review
@PVince81 The problem remains that some files might have a wrong mimetype. I'll fix this to update the wrong mimetypes in a similar way as the updated mimetypes below.