Add Push to hub feature

Add to the backends the Push capabilities to push images that were correctly built.
Also expose them to the CLI, along with KeepImg which was hidden.

pkg/compiler/interface.go

@@ -44,11 +44,11 @@ type CompilerBackendOptions struct {
 }
 
 type CompilerOptions struct {
-	ImageRepository    string
-	PullFirst, KeepImg bool
-	Concurrency        int
-	CompressionType    CompressionImplementation
-	Clean              bool
+	ImageRepository          string
+	PullFirst, KeepImg, Push bool
+	Concurrency              int
+	CompressionType          CompressionImplementation
+	Clean                    bool
 
 	SolverOptions config.LuetSolverOptions
 }
@@ -56,7 +56,8 @@ type CompilerOptions struct {
 func NewDefaultCompilerOptions() *CompilerOptions {
 	return &CompilerOptions{
 		ImageRepository: "luet/cache",
-		PullFirst:       true,
+		PullFirst:       false,
+		Push:            false,
 		CompressionType: None,
 		KeepImg:         true,
 		Concurrency:     runtime.NumCPU(),
@@ -74,6 +75,8 @@ type CompilerBackend interface {
 
 	CopyImage(string, string) error
 	DownloadImage(opts CompilerBackendOptions) error
+
+	Push(opts CompilerBackendOptions) error
 }
 
 type Artifact interface {