aliases: allow configuring the separator

config.sample.json

@@ -12,7 +12,8 @@
   "sources": [
     {
       "type": "aliases",
-      "path": "/etc/mail/aliases"
+      "path": "/etc/mail/aliases",
+      "separator": ":"
     },
     {
       "type": "passwd",

rezelist/backends/aliases.py

@@ -4,6 +4,7 @@ from .. import Address
 class Aliases:
     def __init__(self, config):
         self._path = config["path"]
+        self._separator = config["separator"]
 
     def iter_all(self):
         with open(self._path, "r") as fp:
@@ -12,5 +13,5 @@ class Aliases:
                     continue
                 if line.startswith(":include:"):
                     raise NotImplementedError(":include")
-                addr = line.split(":")[0]
+                addr = line.split(self._separator)[0]
                 yield Address.from_str(addr)