fix: update attestation code to remove library dependencies and shellout for keyless flow (#1442)

Co-authored-by: Alex Goodman <alex.goodman@anchore.com>

syft/event/monitor/generic_task.go

@@ -0,0 +1,23 @@
+package monitor
+
+import (
+	"io"
+
+	"github.com/wagoodman/go-progress"
+)
+
+type ShellProgress struct {
+	io.Reader
+	*progress.Manual
+}
+
+type Title struct {
+	Default      string
+	WhileRunning string
+	OnSuccess    string
+}
+
+type GenericTask struct {
+	Title   Title
+	Context string
+}