Document exported funcs,types,interfaces and enable check. (#475)

* Include EXC0014 and fix issues.
* Include EXC0012 and fix issues.
Signed-off-by: Fabian Kammel <fk@edgeless.systems>
Co-authored-by: Otto Bittner <cobittner@posteo.net>

bootstrapper/internal/clean/clean.go

@@ -10,6 +10,10 @@ import (
 	"sync"
 )
 
+// Cleaner can be used to stop a list of services gracefully.
+// To register an arbitrary amount of stoppers either use New or With.
+// Start needs to be called to ready the Cleaner, then Clean will activate it.
+// Done can be used to wait for Cleaner to run all registered stoppers.
 type Cleaner struct {
 	stoppers  []stopper
 	stopC     chan struct{}