Added Upload Multiple Entity Read Files to specified big query dataset

[michalslowikowski00]

Added example DAG and hook method for Uploading Multiple Entity Read Files to specified big query dataset

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[turbaszek]

@michalslowikowski00 can you rebase please?

[michalslowikowski00]

@turbaszek Rebased. I fixed also variables names and cleaned code a little bit.

[turbaszek]

@michalslowikowski00 mypy is not happy:

airflow/providers/google/marketing_platform/example_dags/example_display_video.py:70: error: Need type annotation for 'CREATE_SDF_DOWNLOAD_TASK_BODY_REQUEST'

[michalslowikowski00]

Yes, I will fix it today, later.

[michalslowikowski00]

@turbaszek I am stupid, I run pre-commit but forgot to push fixes.