move minimum key sizes to config

This moves the minimum key sizes into the config file, so that anyone
can modify the restrictions.

conf/app.ini

@@ -116,6 +116,16 @@ DISABLE_MINIMUM_KEY_SIZE_CHECK = false
 ; Enable captcha validation for registration
 ENABLE_CAPTCHA = true
 
+; used to filter keys which are too short
+[service.minimum_key_sizes]
+ED25519 = 256
+ECDSA   = 256
+NTRU    = 1087
+MCE     = 1702
+McE     = 1702
+RSA     = 1024
+DSA     = 1024
+
 [webhook]
 ; Hook task queue length
 QUEUE_LENGTH = 1000