Forward/back buttons for navigating mail

### Problem

Going back to the last email is cumbersome when the user switches to a new one (intentionally or unintentionally) if they have many mailboxes and or folders.

### Proposal

An incredibly useful way to solve the problem of navigating mail for users with many mailboxes & folders would probably be backwards and forwards buttons like Files and Web.

### Prior Art (Optional)

I'm pretty sure mail for macos an iOS has this.