Added trusted-setup cli arg back in for teku acceptance testing

I think ultimately this should be less important at some point but if it's present it allows me to actually test some changes now, rather than waiting for future builds that build in some changes to teku that remove the need to define trustedSetup, so ideally it's ok to have this defined as a dev flag for testing for now...

The problem I was having was acceptance-tests use custom configuration and there was no way to specify this argument, so I wasn't able to check deneb for external-signer changes in teku...

I've got another change for teku that should make this less important again (default trusted-setup basically) but it'll be hard to coordinate that change plus external-signer changes without some blocking, unless this flag exists, and then i can just start testing things now.

commandline/src/main/java/tech/pegasys/web3signer/commandline/subcommands/Eth2SubCommand.java

@@ -126,6 +126,15 @@ private static class NetworkCliCompletionCandidates extends ArrayList<String> {
       converter = UInt64Converter.class)
   private UInt64 denebForkEpoch;
 
+  @CommandLine.Option(
+      names = {"--Xtrusted-setup"},
+      hidden = true,
+      paramLabel = "<STRING>",
+      description =
+          "The trusted setup which is needed for KZG commitments. Only required when creating a custom network. This value should be a file or URL pointing to a trusted setup.",
+      arity = "1")
+  private String trustedSetup = null; // Depends on network configuration
+
   @CommandLine.Option(
       names = {"--key-manager-api-enabled", "--enable-key-manager-api"},
       paramLabel = "<BOOL>",
@@ -206,6 +215,9 @@ private Eth2NetworkConfiguration createEth2NetworkConfig() {
     if (denebForkEpoch != null) {
       builder.denebForkEpoch(denebForkEpoch);
     }
+    if (trustedSetup != null) {
+      builder.trustedSetup(trustedSetup);
+    }
     return builder.build();
   }