Create service and CLI stub for fast vnodes restore.

[karol-kokoszka]

The service can be located in /pkg/service/<new_restore_service_name> .

Tasks in Scylla Manager are started by the scheduler.

Every "task" service must implement Runner interface

scylla-manager/pkg/service/scheduler/runner.go

Line 17 in 68c99a6

type Runner interface {

that is used by the scheduler to trigger the task.

The stub must consist of the Runner implementation, constructor for the service accepting source-cluster-id, snapshot-id, nodes-mapping and the main method supervising the fast vnodes restore process.

The stub must be connected to the new CLI similar to (

scylla-manager/pkg/cmd/sctool/sctool.go

Line 65 in 61acf93

restoreCmd := restore.NewCommand(&client)

) allowing to trigger the 1-1 restore.

The goal of this task is to have working (but not final) CLI that schedules the 1-1 vnodes restore to start immediately. The main (supervising) restore method from the service stub can just log that "Not yet implemented".