settings: Support free_trial_days in the development environment.

zproject/default_settings.py

@@ -363,7 +363,7 @@ ARCHIVED_DATA_VACUUMING_DELAY_DAYS = 7
 # are available to all realms.
 BILLING_ENABLED = False
 
-FREE_TRIAL_DAYS = None
+FREE_TRIAL_DAYS = get_secret('free_trial_days', None)
 
 # Custom message (supports HTML) to be shown in the navbar of landing pages. Used mainly for
 # making announcements.

zproject/dev_settings.py

@@ -155,7 +155,6 @@ THUMBNAIL_IMAGES = True
 SEARCH_PILLS_ENABLED = bool(os.getenv('SEARCH_PILLS_ENABLED', False))
 
 BILLING_ENABLED = True
-FREE_TRIAL_DAYS = None
 LANDING_PAGE_NAVBAR_MESSAGE = None
 
 # Test Custom TOS template rendering

zproject/test_settings.py

@@ -228,3 +228,5 @@ RATE_LIMITING_RULES = {
     'authenticate_by_username': [],
     'password_reset_form_by_email': [],
 }
+
+FREE_TRIAL_DAYS = None