feat: add multi-account ability

tests/good_test.toml

@@ -4,14 +4,14 @@ db_path="/var/random/scootaloo.sqlite"
 cache_path="/tmp/scootaloo"
 
 [twitter]
-username="tamerelol"
-
 consumer_key="rand consumer key"
 consumer_secret="secret"
 access_key="rand access key"
 access_secret="super secret"
 
 [mastodon]
+[mastodon.tamerelol]
+twitter_screen_name="tamerelol"
 base = "https://m.nintendojo.fr"
 client_id = "rand client id"
 client_secret = "secret"