Make all pkg applications stateful

[jsteenb2]

AC

• if no stack id is provided for application, then one is created
• if stack id is provided, it is used for application
• summary response should return the stackID

note:
it may be worthwhile refactoring the tuples from apply/dry run to be something like

// name is just a stand in, not sure what a name may look like
type PkgDefinition struct {
    StackID influxdb.ID
    Summary Summary
    Diff Diff
}