fix: reconnecting websocket

[pcriadoperez]

• Remove CANCEL read_loop error log. This is not an error as the loop is closed before intentionally.
• Change log debug errors of errors to errors
• Fix error type for when message queue is full
• Return errors to user
• Add tests for ReconnectingWebsocket.py
• Fixes that if first connect fails it would not throw and let the user wait indefinetly
• Improves error handling passing to user error type for different scenarios
• Update docs
• Add websockets_proxy to requirements for python 3.8+

[coveralls]

coverage: 68.112% (+0.6%) from 67.499%
when pulling a3f1081 on pcriadoperez:logs
into 39d7f7a on sammchardy:master.