Fix import error: add missing get_config() function

The contact form and Tor status endpoints were trying to import get_config()
from aisbf.config, but this function didn't exist. Add it as a simple wrapper
that returns the already initialized global config instance.

Fixes the error: cannot import name 'get_config' from 'aisbf.config'

aisbf/config.py

@@ -848,3 +848,6 @@ class Config:
         return self.aisbf
 
 config = Config()
+
+def get_config():
+    return config