Allow users to backup / restore their WSLs using WSL Settings (GUI)

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**Is your feature request related to a problem? Please describe.**
Every time that we want to backup or restore our WSLs, we must use the command line. The **wsl --export** command exports a WSL and **wsl --import** command imports a WSL. For a VHDX backup that belongs to an installed WSL, the command line is **wsl --export --vhd**.

**Describe the solution you'd like**
On WSL Settings (GUI), we want the Backup and Restore options implemented, please. That way, we can export our WSLs to another location for a backup. Also, we can choose to export a VHD if we wish. If our WSLs go wrong, we can import our backed-up ones. Also, we can choose to import a VHD if we wish.

**Describe alternatives you've considered**
We've considered using Microsoft's Power Automate to export / import WSLs. Together, we've added command lines in a flow to export / import WSLs.

**Additional context**
Rather than using WSL's command lines to import or export WSLs, it may be better using WSL Settings (GUI) to back up or restore them.

Start by reviewing WSL Settings and the existing wsl --export and wsl --import command behavior, including the --vhd option. Done means defining and implementing GUI backup and restore flows for distributions and VHDs, with an appropriate way to choose locations and handle failed operations.

Written by the indexing model from the issue text.