refactor: Reduce binary size of zot-minimal; Added CI check for binary size (#1758)

Signed-off-by: Alexei Dodon <adodon@cisco.com>

pkg/common/common.go

@@ -23,6 +23,9 @@ const (
 	CosignSignature   = "cosign"
 	CosignSigKey      = "dev.cosignproject.cosign/signature"
 	NotationSignature = "notation"
+	// same value as github.com/notaryproject/notation-go/registry.ArtifactTypeNotation (assert by internal test).
+	// reason used: to reduce zot minimal binary size (otherwise adds oras.land/oras-go/v2 deps).
+	ArtifactTypeNotation = "application/vnd.cncf.notary.signature"
 )
 
 func Contains[T comparable](elems []T, v T) bool {

pkg/common/common_test.go

@@ -5,6 +5,7 @@ import (
 	"path"
 	"testing"
 
+	notreg "github.com/notaryproject/notation-go/registry"
 	. "github.com/smartystreets/goconvey/convey"
 
 	"zotregistry.io/zot/pkg/api/config"
@@ -56,4 +57,8 @@ func TestCommon(t *testing.T) {
 		So(common.Index([]string{"a", "b"}, "b"), ShouldEqual, 1)
 		So(common.Index([]string{"a", "b"}, "c"), ShouldEqual, -1)
 	})
+
+	Convey("Test ArtifactTypeNotation const has same value as in notaryproject", t, func() {
+		So(common.ArtifactTypeNotation, ShouldEqual, notreg.ArtifactTypeNotation)
+	})
 }