Add supporting documentation for OSPO Helpdesk to ospo-guide repo

Now that we have all these issue templates, we should create a corresponding file called helpdesk.md, where we list out all the services that can be requested via ticket :)

Start by reviewing the existing issue templates in the ospo-guide repository to identify the services that can be requested via ticket. Create helpdesk.md alongside the guide documentation and list the corresponding requestable services. Done means the file exists and covers the services represented by all current templates.

Written by the indexing model from the issue text.