UX Feature Request: prompt to configure backups on install

[Cara Donnelly]

## Context

I recently made a fresh install of Ubuntu 20.04 LTS.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal

## Objective

I finished a long-standing project to properly automate my backups. I designed my solution when I was much less experienced, and it was built from low-level building blocks rather than using a robust and supported solution. Following my old design was a mistake on my part.

## Feature request

Ubuntu should prompt on a fresh install to set up automatic backups using Déjà Dup. This is the default backups manager, but I was not aware that Ubuntu/GNOME/Déjà Dup had made this feature as easy to use as it had.

Adding this prompt would help all users of Ubuntu follow best practices around backups.

## Debug info

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity (not installed)
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon May 4 16:43:20 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
InstallationDate: Installed on 2020-04-27 (6 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: ubiquity
Symptom: installation
UpgradeStatus: No upgrade log present (probably fresh install)