rm experimental Yamux support (#6636)

Author: tersec

beacon_chain/conf.nim

@@ -330,12 +330,6 @@ type
         defaultValue: false
         name: "enr-auto-update" .}: bool
 
-      enableYamux* {.
-        hidden
-        desc: "Enable the Yamux multiplexer"
-        defaultValue: false
-        name: "debug-enable-yamux" .}: bool
-
       weakSubjectivityCheckpoint* {.
         desc: "Weak subjectivity checkpoint in the format block_root:epoch_number"
         name: "weak-subjectivity-checkpoint" .}: Option[Checkpoint]

beacon_chain/conf_light_client.nim

@@ -100,12 +100,6 @@ type LightClientConf* = object
     defaultValue: false
     name: "enr-auto-update" .}: bool
 
-  enableYamux* {.
-    hidden
-    desc: "Enable the Yamux multiplexer"
-    defaultValue: false
-    name: "debug-enable-yamux" .}: bool
-
   agentString* {.
     defaultValue: "nimbus",
     desc: "Node agent string which is used as identifier in network"

beacon_chain/networking/eth2_network.nim

@@ -2249,11 +2249,7 @@ proc newBeaconSwitch(config: BeaconNodeConf | LightClientConf,
                      rng: ref HmacDrbgContext): Switch {.raises: [CatchableError].} =
   let service: Service = WildcardAddressResolverService.new()
 
-  var sb =
-    if config.enableYamux:
-      SwitchBuilder.new().withYamux()
-    else:
-      SwitchBuilder.new()
+  var sb = SwitchBuilder.new()
   # Order of multiplexers matters, the first will be default
 
   sb