Improve the way the Go client logs messages

[tmiddlet2666]

Enhancement Request

We should improve the way log and debug messages are generated in the go client.

This is in response to #123

We should align the log message levels with existing Coherence levels using the COHERENCE_LOG_LEVEL environment variable and deprecate the other environment variables:

• COHERENCE_SESSION_DEBUG
• COHERENCE_MESSAGE_DEBUG
• COHERENCE_RESOLVER_DEBUG

The log levels should be
1 = ERROR
2 = WARNING
3 = INFO (Default)
4 = DEBUG - This will enable the equivalent of COHERENCE_SESSION_DEBUG and COHERENCE_RESOLVER_DEBUG
5 = ALL = this will enable COHERENCE_MESSAGE_DEBUG

[tmiddlet2666]

This will include some of the suggestions from #123 by @mdelapenya

[tmiddlet2666]

Fixed in #125