chore: replace Option with Opt (#4035)

* change all usage of std.options.Option[T] to results.Opt[T]
* fix broken apps and examples (to validate refactor)
* removed all std/options code added for libp2p v2 migration
* add broker Opt codec to persistency/backend_comm.nim
* add a readValue overload for Opt[T] in tools/confutils/cli_args.nim
* keep Option where required (Presto, confutils' config_file.nim)
* Change generateRlnProof error handling
* Fix imports

examples/api_example/api_example.nim

@@ -1,4 +1,3 @@
-import std/options
 import chronos, results, confutils, confutils/defs
 import logos_delivery
 
@@ -67,11 +66,9 @@ when isMainModule:
   if args.ethRpcEndpoint == "":
     # Create a basic configuration for the Waku node
     # No RLN as we don't have an ETH RPC Endpoint
-    conf.mode = Core
     conf.preset = "logos.dev"
   else:
     # Connect to TWN, use ETH RPC Endpoint for RLN
-    conf.mode = Core
     conf.preset = "twn"
     conf.ethClientUrls = @[EthRpcUrl(args.ethRpcEndpoint)]