Logger 3.1.0: Deprecate Levels Timing, APEX, and Sys Context

To help minimize confusion around the various logging levels, Logger will no longer support setting the level for logger.g_timing, logger.g_sys_context, and logger.g_apex. Instead of setting the level to these values, it is recommended to use logger.g_debug when calling logger.set_level.

These levels will still be used/referenced by their appropriate procedures in logger_logs.logger_level.