Add cost API

[hinricht]

Problem description

I want to use the STACKIT Python SDK to query the cost API but I couldn't find a way to do this.

Proposed solution

Searching for cost I found that the cost API/service was implemented, but was removed afterwards ?

See PRs about services/cost/

Why was this removed ?

Alternative solutions (optional)

Additional information

Thanks !

[Manuelvaas]

Hi @hinricht,
thank you for reporting this issue. We will take a look at it.