Clarify / update copy text for ssh-keygen

[loujaybee]

Whilst the better long-term solution here is: #9932. A few users were confused about the password (which is embedded in the command), and why a key is required in order to get SSH access. This is already somewhat explained in the copy text, however, some tweaks could be made to better document the feature and explain better.

[iQQBot]

we remove this requirement, after gen49 workspace cluster deploy