The new "country access" implementation replaces the old
implementation.  Middleware and tests have been updated
accordingly, but deprecated models are preserved
for backwards compatibility.

Add history table for course access rule changes.

Provide test utility for simulating restricted access.

Provide `redirect_if_blocked` method for integration with other
parts of the system (will be used for blocking enrollment).

Add info-level logging explaining when and why users are blocked.

Add Django admin UI for configuring country access

Migrate existing embargo rules into the new tables.

ECOM-996: updated the middleware to use new models and access rules

ECOM-996: added the flag to support old and new formats

ECOM-996: added the api layer for country access settings

ECOM-996: added the api layer for country access settings

ECOM-996 implementing the white and blacklist checks.

ECOM-996 minor re-factoring in api.

ECOM-996 minor re-factoring in api.

ECOM-1025 refactoring the code according to PR feedback.

ECOM-1025 refactoring the code according to PR feedback.

ECOM-1025 deleting cache in model save and delete methods

ECOM-1025 adding basic api test cases file.

ECOM-1025 refactoring the code according to PR feedback.

ECOM-1025 refactoring the code according to PR feedback.

ECOM-1025 refactoring the code according to PR feedback. adding the test cases.

ECOM-1025 removing extra line

ECOM-1025 removing un-used function.

ECOM-1025 removing un-used function.

ECOM-1025 re-factor the code.

ECOM-1025 re-name the test file to test_middleware_access_rules.py. we already had old test_middleware.py

ECOM-1025 adding test cases for newly added models.

ECOM-1025 adding test cases and resolve conflicts.

ECOM-1025 fixing the quality and pep-8 issues.

ECOM-1025 re-factoring the code according to the PR feedback.

ECOM-1025 re-name the variable name.

ECOM-1025 removing the _check_ip_lists and its test cases. also added few missing scenarios test cases.

ECOM-1025 removing un-used line.