Add HTTP attributes to actions in HomeController

[chrrust]

Description

HTTP attributes were missing for actions GetTestUserToken and GetTestOrgToken making them unusable. This PR annotates the actions with HttpGet attribute with a binding to the input parameter so that they can be used again.

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)
• All tests run green

Documentation

• User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[ivarne]

Thank you so much for catching this so quickly and fixing it. I thought I was smart in
#61, but did not check that all endpoints still works. It's hard when the defaults does not solve your issue anymore and you star overriding and it has consequences in other places.