add get_cloud_credentials

[konstan]

Connected to #50

[0xbase12]

Why we should add such funtion in the API.

It's possible to make a function in the user code for that.

If we add such function it will be a mess in some months because there is a lot of combination with our cimi resources.

Imagine if I have added service offer related functions in the API ;).

Cal want to add a workflow abilties but it should not be directly in the API. It can be in another python module.

[konstan]

I need this for HBP MOOC and added it there because there is no option to add it anywhere else. It will then go to credential.py here
https://github.com/slipstream/SlipStreamPythonAPI/tree/issue_%2340-rtp-put-get-sse/api/src/slipstream/api
This is the branch for the migration of run->deployment that was parked. Here is the issue for the partial merge from that branch #52 This was agreed with Cal.