Implement dependency Inversion for runtime pkg - 1

[mayuka-c]

• Instead of returning concrete podman types from runtime methods, use the custom defined types so that the runtime methods can return this custom defined types inorder to achieve dependency inversion.
• This will allow to extend the runtime pkg so that its interface methods can easily be implemented by others (Eg: k8s) other than podman.
• Will be taking up replacing pod and container Inspect types in subsequent PRs as it requires lot of changes.

[mkumatag]

Make sure we use the existing types instead of creating new ones

[mkumatag]

please avoid adding these array kind of structure variables.

[mkumatag]

try to use the already existing Pod type

[mkumatag]

let us see if we can use existing Container type

[mayuka-c]

Make sure we use the existing types instead of creating new ones

Sure I was in a dilemma myself too :)

The main reason I added is because lets say as part of Create Pod Response, we might not be getting all the fields which we have defined in the Pod type. So I thought to define a new type so that the caller while consuming knows that these are the fields populated as part of a method response. With this it will be easier to know at the compile time itself instead of getting default values for those whose fields are not set and we consuming accidentally these fields.

@mkumatag Any suggestions?

[mkumatag]

The main reason I added is because lets say as part of Create Pod Response, we might not be getting all the fields which we have defined in the Pod type. So I thought to define a new type so that the caller while consuming knows that these are the fields populated as part of a method response. With this it will be easier to know at the compile time itself instead of getting default values for those whose fields are not set and we consuming accidentally these fields.

I feel like it's a maintenance headache. All these functions return almost the same thing, except for which fields are optional or mandatory. At the call site, we should just use strict checks if we are expecting specific fields, rather than returning a different type.