sharding (core): Add base sharding support.

Add `meta.args` for command line argument access.
Add command line argument support for shard number.
Add shard count to config file.
Add `meta.sharding` exposing shard properties.
Add shard number to logging methods.
Add shard number to data appid.

bot/meta/sharding.py

@@ -0,0 +1,9 @@
+from .args import args
+from .config import conf
+
+
+shard_number = args.shard or 0
+
+shard_count = conf.bot.getint('shard_count', 1)
+
+sharded = (shard_count > 0)