service: plumb contexts to all (most) threads (#7363)

This continues the push of plumbing contexts through tendermint. I
attempted to find all goroutines in the production code (non-test) and
made sure that these threads would exit when their contexts were
canceled, and I believe this PR does that.

test/e2e/node/main.go

@@ -246,6 +246,10 @@ func startSigner(ctx context.Context, cfg *Config) error {
 			if err := s.Serve(lis); err != nil {
 				panic(err)
 			}
+			go func() {
+				<-ctx.Done()
+				s.GracefulStop()
+			}()
 		}()
 
 		return nil