Make consoleLogLevel default to an env variable setting first

[Channyboy]

The logging element's consoleLogLevel defaults to AUDIT level currently. In order to use logging effectively in environments that manage logs, where env vars are the expected means of applying operational config options, we need consoleLogLevel to be configurable via an env var.

As with other logging configuration, explicitly set bootstrap properties take precedence over environment variables. Explicitly set server.xml attributes take effect once server.xml is read.

env var:
WLP_LOGGING_CONSOLE_LOGLEVEL

bootstrap property (same as today):
com.ibm.ws.logging.console.log.level

server.xml attribute in logging element (same as today):
consoleLogLevel