Description of the Helmholtz cloud is outdated

The Helmholtz Cloud page in hifis.net is a bit outdated. We'd need to:

update screenshots
update list of services
mention orchestration, linking to the new page from !844 (merged)
mention to write to support@hifis.net if you want a new service or a pro-version of a service
...?

@SpickerHZB I can start and let you check/complement?