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.

cmd/devp2p/internal/v5test/framework.go

@@ -60,11 +60,9 @@ type conn struct {
 	remoteAddr *net.UDPAddr
 	listeners  []net.PacketConn
 
-	log           logger
-	codec         *v5wire.Codec
-	lastRequest   v5wire.Packet
-	lastChallenge *v5wire.Whoareyou
-	idCounter     uint32
+	log       logger
+	codec     *v5wire.Codec
+	idCounter uint32
 }
 
 type logger interface {