Explore removing latestv1.Pipeline and latestv1.Artifact from runner & runcontexts everywhere.

[tejal29]

Follow up from #5781 PRs

Support Skaffold cmd parser to have multiple pipeline runners.

We are adding a new render phase in a v2 runner.
This runner should be created when a V3 config is detected. However this is not possible right now.

The runner interface has latestV1 config embedded in it.

type Runner interface {
	Apply(context.Context, io.Writer) error
	ApplyDefaultRepo(tag string) (string, error)
	Build(context.Context, io.Writer, []*latestV1.Artifact) ([]graph.Artifact, error)
	Cleanup(context.Context, io.Writer) error
	Dev(context.Context, io.Writer, []*latestV1.Artifact) error
	Deploy(context.Context, io.Writer, []graph.Artifact) error
	DeployAndLog(context.Context, io.Writer, []graph.Artifact) error
	GeneratePipeline(context.Context, io.Writer, []*latestV1.SkaffoldConfig, []string, string) error
	HasBuilt() bool
	HasDeployed() bool
	Prune(context.Context, io.Writer) error
	Render(context.Context, io.Writer, []graph.Artifact, bool, string) error
	Test(context.Context, io.Writer, []graph.Artifact) error
}

Similarly see RunContext has latestv1.Pipeline embedded in the struct.

The current V2 runner has the following methods

Dev(ctx context.Context, out io.Writer, artifacts []*latestV1.Artifact) error
GeneratePipeline(ctx context.Context, out io.Writer, configs []*latestV1.SkaffoldConfig, configPaths []string, fileOut string) error
Render(ctx context.Context, out io.Writer, builds []graph.Artifact, offline bool, filepath string) 

where []graph.Artifact has latestV1.Artifact field.

However, the V2 runner is expected to see a latestV2.Artifact and latestV2.SkaffoldConfig. If we make that change, the v2 runner will not adhere by runner.Runner interface.
This will mean, we will have to duplicate all code in cmd package e.g. cmd.createNewRunner to return a v2 runner.

It would be great

1. if we can keep the code in cmd package as is
2. have less duplication in pkg/runner.Build functions as build is going to be the same.

Device a plan to remove the version embedded in Runner interface, RunContext struct.

[tejal29]

@tejal29 to add more description.
Should be done by v1.28.0 milestone to make sure we can achieve the target date of july end for skaffold render.