Add an option for “all/unspecified/default” capabilities

[stevejburge]

This is an interesting idea:
https://wordpress.org/support/topic/unpaid-version-is-not-useful/

Add an option for “all/unspecified/default” so that if new roles are created, they can adopt the permissions that have been set up instead of being unrestricted, since it’s highly likely that the dev adding the role will know to even check such a thing.

If you allow roles to be automatically added to new roles, we could make life easier for sites with lots of roles. Here's how it could work:

• Click "New Role"
• On the Capabilities screen, several capabilities are set as "default" and are already filled in. Examples could be "read" and "edit_posts"

The key would be where to set "Default" next to individual capabilities