Create single license scanner for all catalogers (#3348)

* add single license scanner instance

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* rename testing license scanner

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

internal/licenses/context.go

@@ -0,0 +1,18 @@
+package licenses
+
+import (
+	"context"
+)
+
+type licenseScannerKey struct{}
+
+func SetContextLicenseScanner(ctx context.Context, s Scanner) context.Context {
+	return context.WithValue(ctx, licenseScannerKey{}, s)
+}
+
+func ContextLicenseScanner(ctx context.Context) Scanner {
+	if s, ok := ctx.Value(licenseScannerKey{}).(Scanner); ok {
+		return s
+	}
+	return NewDefaultScanner()
+}