opencost struct types update

[Azanul]

Problem

All Opencost fields are float64 in their structs and number in swagger. Using int on our end may cause issues.

ref:-

• https://github.com/opencost/opencost/blob/develop/docs/swagger.json
• https://github.com/opencost/opencost/blob/6a7d9ada3cd0422701c90b5df214b8bf322b0e62/pkg/kubecost/allocation_json.go#L13

Solution

Converted all int fields to float64 in opencost costdata struct.

Changes Made

• Added the references as code comments
• Converted all int fields to float64 in the relevant struct.
• Added more fields which might be useful in the future

Checklist

• Code follows the contributing guidelines
• Changes have been thoroughly tested
• Documentation has been updated, if necessary
• Any dependencies have been added to the project, if necessary

Reviewers

@mlabouardy
@AvineshTripathi

[mlabouardy]

LGTM!