stream: shift websocket reader and dialer code from wrapper to stream package

[shazbert]

PR Description

~~Opened as draft for initial inspection and critique.~~ This attempts to reduce code duplication for websocket wrappers and gets it another step forward for multi-connection handling.

• Define websocket processor handlers per individual connection - This will eventually be bespoke connections only handling specific assets and or constrained subs.
• Define bootstrap function for bespoke connection startup code per individual connection
• Shift connection dialing and session handling away from wrappers
• Shift websocket reader routines generation to stream package
• Remove proxy field websocket connection as its handled 1 proxy per session anyway
• Adds basic (non-tls) mock server and mock proxy for websocket testing
• Remove superfluous running URL fields as connections can differ
• Adds new currency error ErrCurrencyPairRequired
• Split SetWebsocketURL into two functions SetWebsocketURL && SetWebsocketAuthURL
• Split GetWebsocketURL into two functions GetWebsocketURL && GetWebsocketAuthURL
• Removes unused websocket field DefaultURL
• Removes unexported methods setState, setEnabled, setDataMonitorRunning, dataMonitorRunning, checkAndSetMonitorRunning, setTrafficMonitorRunning, setConnectionMonitorRunning and use the field methods directly.
• Defered reader.Close in parseBinaryResponse() so as to make sure if io.ReadAll fails it will still close.

Websocket_Connection

• Remove setConnectedStatus and IsConnected methods in favour of field methods.

Fixes # (issue)

Type of change

Please delete options that are not relevant and add an x in [] as item is complete.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How has this been tested

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration and also consider improving test coverage whilst working on a certain feature or package.

• [ ] go test ./... -race
• [ ] golangci-lint run
• [ ] Test X

Checklist

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation and regenerated documentation via the documentation tool
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally and on Github Actions with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 61.06557% with 95 lines in your changes are missing coverage. Please review.

Project coverage is 37.78%. Comparing base (d679a76) to head (5af9fea). Report is 3 commits behind head on master.

:exclamation: Current head 5af9fea differs from pull request most recent head 8e9bf16. Consider uploading reports for the commit 8e9bf16 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1493      +/-   ##
==========================================
+ Coverage   35.89%   37.78%   +1.88%     
==========================================
  Files         411      411              
  Lines      177595   147708   -29887     
==========================================
- Hits        63752    55815    -7937     
+ Misses     106058    84092   -21966     
- Partials     7785     7801      +16     

Files	Coverage Δ
currency/code.go	89.17% <ø> (+1.12%)	:arrow_up:
exchanges/binance/binance_wrapper.go	41.09% <100.00%> (+2.87%)	:arrow_up:
exchanges/binance/type_convert.go	60.75% <ø> (+7.15%)	:arrow_up:
exchanges/binanceus/binanceus_wrapper.go	43.88% <100.00%> (+3.80%)	:arrow_up:
exchanges/bitfinex/bitfinex_wrapper.go	40.54% <100.00%> (+3.97%)	:arrow_up:
exchanges/bithumb/bithumb.go	41.42% <100.00%> (+2.14%)	:arrow_up:
exchanges/bithumb/bithumb_wrapper.go	40.86% <100.00%> (+3.18%)	:arrow_up:
exchanges/bitmex/bitmex_wrapper.go	47.60% <100.00%> (+2.39%)	:arrow_up:
exchanges/bitstamp/bitstamp_wrapper.go	57.97% <100.00%> (+5.79%)	:arrow_up:
exchanges/btcmarkets/btcmarkets_wrapper.go	33.41% <100.00%> (+2.87%)	:arrow_up:
... and 26 more

... and 351 files with indirect coverage changes

[shazbert]

Closing in favour of #1580.