feat: Enable user and pass authentification

Token is not the only way to authentificate to gitea. Using credentials
should also be enabled.

When initializing the Gitea object, the token, the auth or none of them
can be provided.

gitea/gitea.py

@@ -19,17 +19,30 @@ class Gitea:
     CREATE_ORG = """/admin/users/%s/orgs"""  # <username>
     CREATE_TEAM = """/orgs/%s/teams"""  # <orgname>
 
-    def __init__(self, gitea_url: str, token_text: str, log_level="INFO"):
+    def __init__(
+            self,
+            gitea_url: str,
+            token_text=None,
+            auth=None,
+            log_level="INFO"
+        ):
         """ Initializing Gitea-instance."""
         self.logger = logging.getLogger(__name__)
         self.logger.setLevel(log_level)
         self.headers = {
-            "Authorization": "token " + token_text,
             "Content-type": "application/json",
         }
         self.url = gitea_url
         self.requests = requests.Session()
 
+        # Manage authentification
+        if not token_text and not auth:
+            raise ValueError("Please provide auth or token_text, but not both")
+        if token_text:
+            self.headers["Authorization"] = "token " + token_text
+        if auth:
+            self.requests.auth = tuple(auth.split(":"))
+
     def __get_url(self, endpoint):
         url = self.url + "/api/v1" + endpoint
         self.logger.debug("Url: %s" % url)