remove all default keys (#1485)

This change:
- Generates a new BitTorrent pepper by default
- Generates a new pagination key by default
- Changes the pagination key format to base64
- Removes selfsigned JWT certs
- Moves test keys to test/data

util/security/crypto.py

@@ -4,12 +4,12 @@ from cryptography.fernet import Fernet, InvalidToken
 
 def encrypt_string(string, key):
   """ Encrypts a string with the specified key. The key must be 32 raw bytes. """
-  f = Fernet(base64.urlsafe_b64encode(key))
+  f = Fernet(key)
   return f.encrypt(string)
 
 def decrypt_string(string, key, ttl=None):
   """ Decrypts an encrypted string with the specified key. The key must be 32 raw bytes. """
-  f = Fernet(base64.urlsafe_b64encode(key))
+  f = Fernet(key)
   try:
     return f.decrypt(str(string), ttl=ttl)
   except InvalidToken: