replace add service functionality in settings page with dedicated "services" page

[juriroemer]

• [x] service page is like projects page but for services
• [x] services have labels "activated" oder "not activated"
• [x] expansion panels contain description of the services (served through the ports object by the backend)
• [x] expansion panels contain buttons do activate/deactivate the service
• [x] services page will have "activate at least one service to use RDS" note, if no services are activated

[juriroemer]

If welcome page redirects to projects page, the

• [x] projects page should also include "activate at least one service to use RDS" note, if no services are activated

[Heiss]

done