…TE_CONFIG_DELETED and COURSE_CERTIFICATE_CONFIG_CHANGED to send cert config data onto Credentials service

…when course import happened.

…gnal, emit_course_certificate_config_deleted_signal when course config data is changing in Studio UI

…als.

…ificatesDetailHandler to be sure that certificate config data signals are emiting

… HelperMethods are ready to more common usage.

… openedx-events package.

…rtificate configs to credentials (#2465)

* refactor: [EDXOLDMNG-224] Moves course certificate configuration creation and deletion to separate functions.

* feat: [EDXOLDMNG-218] uses course id instead of course key for CertificateConfigData container

* test: [EDXOLDMNG-224] updates SignalCourseCertificateConfigurationListenerTestCase tests in order refactoring the approach to send data to Credentials via http.

* test: [EDXOLDMNG-224] creates tests for course certificate configuration credentials utils apis.

* feat: [EDXOLDMNG-224] Creates manage.py command to migrate course certificate coniguration.

* refactor: [EDXOLDMNG-224] code polishing for migrate cert config command.

* docs: [EDXOLDMNG-224] adds doc string for migrate_cert_config command's main class