Adding new reviewers - UX / QoL improvement

Is your feature request related to a problem? Please describe.
"We are now using Janeway to handle the new RHETM submissions. Mostly it’s been a breeze, but there is one thing we can’t seem to master very well: the process of adding new reviewers to the platform. Whenever we do this by clicking on ‘Add Reviewer’ in the peer review page, this prompts us to select a reviewer from the existing list. As most of our reviewers are not yet on the list, we then click on ‘Add New Reviewer’, which brings us to a page where we must create a new user. This is where it gets clunky: not only does the page force us to enter a password for the new user, but the users apparently are not notified of this action. They only receive an email later, when we assign them to the submission and invite them to write a review. But then they don’t know how to access the platform (and don’t receive any instructions to this effect). After simulating the situation with a fake user, I discovered the solution is to click on ‘Forgot my password’ and thus recover access to the account. But this is not very intuitive, and people keep writing us back to ask how to proceed."

Additional context
Feedback from #FD8391