Support both wss and ws for trusted node in delayed_node plugin

**User Story**

As a node admin I'd like to be able to run a delayed node with a 3rd-party trusted node that only supports secure websocket connection (`wss://`) E.G. a public API node so that I don't have to run 2 nodes.

**Impacts**
Describe which portion(s) of BitShares Core may be impacted by your request. Please tick at least one box.
- [ ] API (the application programming interface)
- [ ] Build (the build process or something prior to compiled code)
- [ ] CLI (the command line wallet)
- [x] Deployment (the deployment process after building such as Docker, Travis, etc.)
- [ ] DEX (the Decentralized EXchange, market engine, etc.)
- [ ] P2P (the peer-to-peer network for transaction/block propagation)
- [ ] Performance (system or user efficiency, etc.)
- [ ] Protocol (the blockchain logic, consensus, validation, etc.)
- [ ] Security (the security of system or user data, etc.)
- [ ] UX (the User Experience)
- [ ] Other (please add below)

## CORE TEAM TASK LIST
- [ ] Evaluate / Prioritize Feature Request
- [ ] Refine User Stories / Requirements
- [ ] Define Test Cases
- [ ] Design / Develop Solution
- [ ] Perform QA/Testing
- [ ] Update Documentation

Start by locating the delayed_node plugin and its trusted-node websocket configuration. Trace how the trusted node URL is parsed and connected, then verify that both ws:// and wss:// endpoints are accepted and usable without requiring two nodes.

Written by the indexing model from the issue text.