Removed role 'name' field from database

Removed role 'name' field from database

The 'name' field was really redundant and caused confusion in the
codebase, since the 'Display' name is often used and we have a
'system_name' for the admin and public role.

This fixes #2032, Where external auth group matching has confusing
behaviour as matching was done against the display_name, if no
external_auth field is set, but only roles with a match 'name' field
would be considered.

This also fixes and error where the role users migration, on role
delete, would not actually fire due to mis-matching http body keys.
Looks like this has been an issue from the start. Added some testing to
cover. Fixes #2211.

Also converted phpdoc to typehints in many areas of the reviewed code
during the above.