Show more statistics in console

**User Story**

As a node admin I want to see more statistics in console, E.G.
* number of peers that are currently connected to my node
* number of websocket API clients connected
* number of API requests served in last x seconds

Currently we only have these:
>1188274ms th_a application.cpp:532 handle_block ] Got block: #39537050 025b499a44481e82d0baf058549db1de97ef3331 time: 2019-07-26T21:19:48 transaction(s): 26 latency: 274 ms from: bhuz irreversible: 39537033 (-17)
1189287ms th_a application.cpp:592 handle_transaction ] Got 13 transactions from network
1190343ms th_a application.cpp:592 handle_transaction ] Got 10 transactions from network

**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)
- [ ] 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.)
- [x] UX (the User Experience)
- [ ] Other (please add below)

**Additional Context (optional)**
Add any other context about your request here.

## 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 reading the existing logging paths in application.cpp, especially handle_block and handle_transaction, to understand which node activity is already reported in the console. Define the required statistics and their time window before locating the peer and websocket API connection entry points. Done means the requested node, client, and recent-request statistics are visible in the console and covered by appropriate tests.

Written by the indexing model from the issue text.