Logging enhancements and cleanup (#2502)

* Logging enhancements and cleanup

- Removed debug log messages every time `Config.get_conf` is used or a JSON file is read/saved. The basic configuration is now logged once with DEBUG when the bot starts up instead.
- Changed logging output format to reverse date order, include seconds, and use the logger's name instead of the module, function and line number.
- Log files are now kept in the `DATAPATH/core/logs` directory. Each time Red is restarted, a new log is created, and the old ones renamed in a rotating fashion. There can be a maximum of 9 logs in total.
- Each log file now has a smaller max size of 500KB before it will be split into multiple parts. There are also a maximum of 9 parts of each log.
- Discord.py logger now uses the same output formatter as red's loggers
- Moved logging setup code into `redbot.logging` module.

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Reformat

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Implement discussed changes

- We maintain a red.log over multiple runtimes, alongside a latest.log and previous.log for individual runtimes.
- Naming convention changed a bit. E.g. when latest.log is just one part, it will be named latest.log. When it becomes two parts, they will both be named latest-part1.log and latest-part2.log.
- Rotation direction is reversed. This means as the files end up being named in chronological order.

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

redbot/core/config.py

@@ -569,13 +569,9 @@ class Config:
         # We have to import this here otherwise we have a circular dependency
         from .data_manager import basic_config
 
-        log.debug("Basic config: \n\n{}".format(basic_config))
-
         driver_name = basic_config.get("STORAGE_TYPE", "JSON")
         driver_details = basic_config.get("STORAGE_DETAILS", {})
 
-        log.debug("Using driver: '{}'".format(driver_name))
-
         driver = get_driver(
             driver_name, cog_name, uuid, data_path_override=cog_path_override, **driver_details
         )