Feature to do dry-run/diff of remote to local

[pan-mroku]

Pre-Submission checklist

• [x] There is no existing issue that already asks for this feature.
  
• [x] The feature already exists in rclone (on your PC or in Termux)
• [?] I am prepared to help make this feature - I've never touched android code and I don't know how easy to understand to me RCX code would be

What version of RCX are you using (About -> App version)?

1.12.2

What problem are you trying to solve?

I use pcloud to store my files. Some are markdown notes, PDF files, images, etc. I want to have these in three places: remote - so I have a backup PC - sometimes I have to use PC to organize my files phone - most often I use my phone to edit my files The problem is that sometimes I might get confused in which copy (PC or phone) needs to be updated. In general the flow is that after modifying something I try to remember and update remote. But that can fail. When I'm on the go and want to modify files on phone, I am not always sure if I can just upload, or should I take care because version on phone might differ from remote more than what I want to upload. On PC it's not a problem, because my rclone script first executes with --dry-run so I can inspect which files will be touched and gives me ability to do "cp up", "cp down", "sync up", "sync down"

What should RCX be able to do differently to help with this problem?

Apart from "sync remote to local" and "sync local to remote" it would be nice to have something like "diff remote and local" where it would show a list of files and what are the differences (new/last changed/deleted) between remote and local. That way I could inspect the differences before the actual sync