When using Connect-AzAccount -DeviceAuth, consider copying the code to the clipboard

## Description of the new feature

For a more seamless login experience, I already have setup a shortcut to the `https://microsoft.com/devicelogin` page on my browser. It would be great if the device code were automatically copied to the clipboard when running this command.

## Proposed implementation details (optional)

Before displaying the notice to use a web browser, navigate to the device login page and enter a particular code, the said code could be copied to the clipboard of the user. Maybe a command-line flag could allow the user to opt-in to this behaviour if this is considered a breaking change to wipe whatever is in the clipboard for the user.

Start at the Connect-AzAccount -DeviceAuth entry point and trace where the device code is displayed before browser instructions are shown. Determine how clipboard copying and any opt-in flag should fit that flow; done means the device code is copied without unexpectedly overwriting the clipboard, with the requested login behavior covered.

Written by the indexing model from the issue text.