All of our install/admin scripts had a try/except block calling the
main function and handling common exceptions. These were copy-pasted
from each other and modified to various levels of sophistication.
This refactors them out of installers to a single function, which
includes a final pass/fail message for all of the scripts.
Non-install scripts that set up the same log handler levels for
stderr and log file are not changed, as it's not possible to log
to only the logfile without changing the logger configuration.
https://fedorahosted.org/freeipa/ticket/2071
change default_logger_level to debug in configure_standard_logging
add new ipa_log_manager module, move log_mgr there, also export
root_logger from log_mgr.
change all log_manager imports to ipa_log_manager and change
log_manager.root_logger to root_logger.
add missing import for parse_log_level()
