Created announcement service and fixed some names on folders and folders

bbcli/Services/AnnouncementService.py

bbcli/Services/CourseAnnouncementService.py

bbcli/Services/__init__.py

bbcli/__init__.py

bbcli/cli.py

bbcli/entities/RequestData.py

bbcli/entities/__init__.py

bbcli/services/ContentService.py

bbcli/services/__init__.py

bbcli/services/announcement_service.py

bbcli/services/authorization_service.py

bbcli/services/course_service.py

bbcli/utils/utils.py