Finished course and announcement core functionality

bbcli/__main__.py

bbcli/__pycache__/string_builder.cpython-38.pyc

bbcli/cli.py

bbcli/commands/announcements.py

bbcli/commands/contents.py

bbcli/commands/courses.py

bbcli/controllers/announcement_controller.py

bbcli/services/announcements_service.py

bbcli/services/contents_service.py

bbcli/services/courses_service.py

bbcli/utils/URL_builder.py

bbcli/views/announcement_view.py