Option to migrate without wp-cli

[audunmb]

It would be really nice to have the option to migrate all users to authors when you don't have access to wp-cli. In a hosted enviroment wp-cli is seldom an option, which makes it difficult to migrate.

I have 152 authors on my site (old site, lots of guest authors) which now are registered as users, most of them should be added as guest authors instead, but I don't have access to wp-cli on my hosting.

An option to migrate all users to guest authors from the WP dashboard UI would be nice.