[FEATURE] Add a view and model to add an admin

**Is your feature request related to a problem? Please describe.**
Add a feature to add admin to the platform. Configure database.

**Describe the solution you'd like**
An admin can register on the platform and configure his profile. Using Django admin dashboard, add courses category and courses related features
**Describe alternatives you've considered**

**Additional context**
Any other admin tasks for courses management

### All Submissions:

* [ ] Have you followed the guidelines in our Contributing document?
* [ ] Have you checked to ensure there aren't other open [Pull Requests](../../../pulls) for the same update/change?

### New Feature Submissions:

1. [ ] Does your submission pass tests?
2. [ ] Have you lint your code locally prior to submission?

### Changes to Core Features:

* [ ] Have you added an explanation of what your changes do and why you'd like us to include them?
* [ ] Have you written new tests for your core changes, as applicable?
* [ ] Have you successfully ran tests with your changes locally?