all: more linters (#24783)

This enables the following linters

- typecheck
- unused
- staticcheck
- bidichk
- durationcheck
- exportloopref
- gosec

WIth a few exceptions.

- We use a deprecated protobuf in trezor. I didn't want to mess with that, since I cannot meaningfully test any changes there.
- The deprecated TypeMux is used in a few places still, so the warning for it is silenced for now.
- Using string type in context.WithValue is apparently wrong, one should use a custom type, to prevent collisions between different places in the hierarchy of callers. That should be fixed at some point, but may require some attention.
- The warnings for using weak random generator are squashed, since we use a lot of random without need for cryptographic guarantees.

les/flowcontrol/manager.go

@@ -58,10 +58,9 @@ var (
 // corrigated buffer value and usually allows a higher remaining buffer value
 // to be returned with each reply.
 type ClientManager struct {
-	clock     mclock.Clock
-	lock      sync.Mutex
-	enabledCh chan struct{}
-	stop      chan chan struct{}
+	clock mclock.Clock
+	lock  sync.Mutex
+	stop  chan chan struct{}
 
 	curve                                      PieceWiseLinear
 	sumRecharge, totalRecharge, totalConnected uint64