Global code ovehaul - remove CAS and other, add 15 minute greet check

- Remove CAS, as it no longer works for us
- Remove other checks
- Implement 15 minute greet timeout check
- Fix chat logos
- Ditch thirdparty logger, use stdlib log facility wrapper for logging

data/config-example.json

@@ -1,9 +1,6 @@
 {
-	"name": "Bunny",
 	"token": "get_it_from_botfather",
 	"loglevel": "debug",
-        "logfile": "bunny-bot.log",
-        "logchats": false,
-	"csign": ".",
-	"datadir": "data"
+	"logfile": "/var/log/bunny-bot/bunny-bot.log",
+	"chat_logs": "chat_logs"
 }