(bot_admin): Add status updates and guild logs.

New guild log config for posting joined/left guilds.
New status updater to show voice channel activity.

bot/modules/sysadmin/status.py

@@ -0,0 +1,59 @@
+import time
+import asyncio
+import discord
+from meta import client
+
+from .module import module
+
+
+_last_update = 0
+
+
+async def update_status():
+    # TODO: Make globally configurable and saveable
+    global _last_update
+
+    if time.time() - _last_update < 30:
+        return
+
+    _last_update = time.time()
+
+    student_count = sum(
+        len(ch.members)
+        for guild in client.guilds
+        for ch in guild.voice_channels
+    )
+    room_count = sum(
+        len([vc for vc in guild.voice_channels if vc.members])
+        for guild in client.guilds
+    )
+    status = "{} students in {} study rooms!".format(student_count, room_count)
+
+    await client.change_presence(
+        activity=discord.Activity(
+            type=discord.ActivityType.watching,
+            name=status
+        )
+    )
+
+
+@client.add_after_event("voice_state_update")
+async def trigger_status_update(client, member, before, after):
+    if before.channel != after.channel:
+        await update_status()
+
+
+async def _status_loop():
+    while not client.is_ready():
+        await asyncio.sleep(5)
+    while True:
+        try:
+            await update_status()
+        except discord.HTTPException:
+            pass
+        await asyncio.sleep(300)
+
+
+@module.launch_task
+async def launch_status_update(client):
+    asyncio.create_task(_status_loop())