🍒kcms/kded: allow users to enable disabled-by-default services

Some KDED services are optional and not loaded on startup by default. Previously those services are ignored and not displayed in the KCM, and the user can only enable those services by editing the config file.

This adds a new group type named "ManualType" to list those services so the user can also enable those services in the KCM easily.

(cherry picked from commit 737df53e)

Co-authored-by: Fushan Wen qydwhotmail@gmail.com