cmd/geth, node: allow configuring JSON-RPC on custom path prefix (#22184)

This change allows users to set a custom path prefix on which to mount the http-rpc
or ws-rpc handlers via the new flags --http.rpcprefix and --ws.rpcprefix.

Fixes #21826

Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/geth/usage.go

@@ -138,12 +138,14 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			utils.HTTPListenAddrFlag,
 			utils.HTTPPortFlag,
 			utils.HTTPApiFlag,
+			utils.HTTPPathPrefixFlag,
 			utils.HTTPCORSDomainFlag,
 			utils.HTTPVirtualHostsFlag,
 			utils.WSEnabledFlag,
 			utils.WSListenAddrFlag,
 			utils.WSPortFlag,
 			utils.WSApiFlag,
+			utils.WSPathPrefixFlag,
 			utils.WSAllowedOriginsFlag,
 			utils.GraphQLEnabledFlag,
 			utils.GraphQLCORSDomainFlag,