Update callback url for SSO and favorite API call (fossasia#200)

* update base_path using force_script_name

* fix black style, using url template

* correct sso login url

* update sso url using url template

* update callback url base on base path

* update default base_path

* fix UI, remove default base path

* update api url for favorite call

src/pretalx/common/templates/common/auth.html

@@ -33,7 +33,7 @@
  {% endif %}
  <div class="panel panel-default">
  <div class="panel-heading text-center" id="headingOne">
- <a class="btn btn-lg btn-primary btn-block mt-3" href="/login">
+ <a class="btn btn-lg btn-primary btn-block mt-3" href='{% url "eventyay_common:oauth2_provider.login" %}'>
  {% translate "Login with SSO" %}
  </a>
  </div>

src/pretalx/settings.py

@@ -719,7 +719,7 @@ def merge_csp(*options, config=None):
  "CLIENT_SECRET": SSO_CLIENT_SECRET,
  "AUTHORIZE_URL": "/".join([EVENTYAY_TICKET_BASE_PATH, "control/oauth2/authorize/"]),
  "ACCESS_TOKEN_URL": "/".join([EVENTYAY_TICKET_BASE_PATH, "control/oauth2/token/"]),
- "REDIRECT_URI": "/".join([SITE_URL, "oauth2/callback/"]),
+ "REDIRECT_URI": "/".join([SITE_URL, BASE_PATH[1:], "oauth2/callback/"]),
  "SCOPE": ["profile"],
 }
 # Set default Application model if using default
@@ -734,6 +734,6 @@ def merge_csp(*options, config=None):
 OAUTHLIB_INSECURE_TRANSPORT = True
 
 LOGOUT_REDIRECT_URL = "/"
-LOGIN_URL = "/login/"
+LOGIN_URL = BASE_PATH + "/login/"
 
 CORS_ORIGIN_WHITELIST = [EVENTYAY_TICKET_BASE_PATH]