Add client_id and client_secret fields to Insights credential

[fosterseth]

Adds client_id and client_secret fields to the existing insights credential so that users can authenticate with a service account instead of basic auth

so users should either use username/password, or client_id/client_secret

if client_id is set, then authentication method is set to "service_account" automatically

[chrismeyersfsu]

Looks like this will work if your plan is to consume it in the project update, but I think you will need to define a custom_injectors for this to work for the inventory update case.

edit: Actually, maybe not. But something over in inventory plugin land will need to be updated to produce

plugin: redhat.insights.insights

authentication: basic
user: "insights username"
password: "insights password"

OR

plugin: redhat.insights.insights
authentication: service_account
client_id: "service account client-id"
client_secret: "service account client-secret"