add blog feature in django admin

[openrijal]

Details of PR

• create blog admin app
• create blog base template
• new migrations

Steps to test

• checkout the branch
• create a superuser: ./manage.py createsuperuser and follow the prompts (this will only affect your local system)
• run the migration ./manage.py migrate
• run the local server ./manage.py runserver
• login to django admin using the superuser credentials /admin
• you should be able to see a section for Blog Entries and be able to add, edit and delete blog entries

Screenshots