feat(cve): implement CVE scanning as background tasks (#1833)

1. Move existing CVE DB download generator/task login under the cve package
2. Add a new CVE scanner task generator and task type to run in the background, as well as tests for it
3. Move the CVE cache in its own package
4. Add a CVE scanner methods to check if an entry is present in the cache, and to retreive the results
5. Modify the FilterTags MetaDB method to not exit on first error
This is needed in order to pass all tags to the generator,
instead of the generator stopping at the first set of invalid data
6. Integrate the new scanning task generator with the existing zot code.
7. Fix an issue where the CVE scan results for multiarch images was not cached
8. Rewrite some of the older CVE tests to use the new image-utils test package
9. Use the CVE scanner as attribute of the controller instead of CveInfo.
Remove functionality of CVE DB update from CveInfo, it is now responsible,
as the name states, only for providing CVE information.
10. The logic to get maximum severity and cve count for image sumaries now uses only the scanner cache.
11. Removed the GetCVESummaryForImage method from CveInfo as it was only used in tests

Signed-off-by: Andrei Aaron <aaaron@luxoft.com>

pkg/cli/client/cve_cmd_internal_test.go

@@ -531,7 +531,7 @@ func TestNegativeServerResponse(t *testing.T) {
 			panic(err)
 		}
 
-		ctlr.CveInfo = getMockCveInfo(ctlr.MetaDB, ctlr.Log)
+		ctlr.CveScanner = getMockCveScanner(ctlr.MetaDB)
 
 		go func() {
 			if err := ctlr.Run(ctx); !errors.Is(err, http.ErrServerClosed) {
@@ -606,7 +606,7 @@ func TestServerCVEResponse(t *testing.T) {
 		panic(err)
 	}
 
-	ctlr.CveInfo = getMockCveInfo(ctlr.MetaDB, ctlr.Log)
+	ctlr.CveScanner = getMockCveScanner(ctlr.MetaDB)
 
 	go func() {
 		if err := ctlr.Run(ctx); !errors.Is(err, http.ErrServerClosed) {
@@ -947,39 +947,35 @@ func TestCVESort(t *testing.T) {
 		panic(err)
 	}
 
-	ctlr.CveInfo = cveinfo.BaseCveInfo{
-		Log:    ctlr.Log,
-		MetaDB: mocks.MetaDBMock{},
-		Scanner: mocks.CveScannerMock{
-			ScanImageFn: func(image string) (map[string]cvemodel.CVE, error) {
-				return map[string]cvemodel.CVE{
-					"CVE-2023-1255": {
-						ID:       "CVE-2023-1255",
-						Severity: "LOW",
-						Title:    "Input buffer over-read in AES-XTS implementation and testing",
-					},
-					"CVE-2023-2650": {
-						ID:       "CVE-2023-2650",
-						Severity: "MEDIUM",
-						Title:    "Possible DoS translating ASN.1 object identifier and executer",
-					},
-					"CVE-2023-2975": {
-						ID:       "CVE-2023-2975",
-						Severity: "HIGH",
-						Title:    "AES-SIV cipher implementation contains a bug that can break",
-					},
-					"CVE-2023-3446": {
-						ID:       "CVE-2023-3446",
-						Severity: "CRITICAL",
-						Title:    "Excessive time spent checking DH keys and parenthesis",
-					},
-					"CVE-2023-3817": {
-						ID:       "CVE-2023-3817",
-						Severity: "MEDIUM",
-						Title:    "Excessive time spent checking DH q parameter and arguments",
-					},
-				}, nil
-			},
+	ctlr.CveScanner = mocks.CveScannerMock{
+		ScanImageFn: func(image string) (map[string]cvemodel.CVE, error) {
+			return map[string]cvemodel.CVE{
+				"CVE-2023-1255": {
+					ID:       "CVE-2023-1255",
+					Severity: "LOW",
+					Title:    "Input buffer over-read in AES-XTS implementation and testing",
+				},
+				"CVE-2023-2650": {
+					ID:       "CVE-2023-2650",
+					Severity: "MEDIUM",
+					Title:    "Possible DoS translating ASN.1 object identifier and executer",
+				},
+				"CVE-2023-2975": {
+					ID:       "CVE-2023-2975",
+					Severity: "HIGH",
+					Title:    "AES-SIV cipher implementation contains a bug that can break",
+				},
+				"CVE-2023-3446": {
+					ID:       "CVE-2023-3446",
+					Severity: "CRITICAL",
+					Title:    "Excessive time spent checking DH keys and parenthesis",
+				},
+				"CVE-2023-3817": {
+					ID:       "CVE-2023-3817",
+					Severity: "MEDIUM",
+					Title:    "Excessive time spent checking DH q parameter and arguments",
+				},
+			}, nil
 		},
 	}
 
@@ -1373,7 +1369,7 @@ func TestCVECommandErrors(t *testing.T) {
 	})
 }
 
-func getMockCveInfo(metaDB mTypes.MetaDB, log log.Logger) cveinfo.CveInfo {
+func getMockCveScanner(metaDB mTypes.MetaDB) cveinfo.Scanner {
 	// MetaDB loaded with initial data now mock the scanner
 	// Setup test CVE data in mock scanner
 	scanner := mocks.CveScannerMock{
@@ -1472,11 +1468,7 @@ func getMockCveInfo(metaDB mTypes.MetaDB, log log.Logger) cveinfo.CveInfo {
 		},
 	}
 
-	return &cveinfo.BaseCveInfo{
-		Log:     log,
-		Scanner: scanner,
-		MetaDB:  metaDB,
-	}
+	return &scanner
 }
 
 type mockServiceForRetry struct {