BO35 - Create a DAL function to update or delete the map's marker's icon

[gregoriopalama]

Add a DAL function in the Venue API.

The function should accept the image for the marker. It should be the actual image that the function will save on Firebase Storage. In the document on Firestore, we will save only the public link to the saved image.

The response will be an error if something goes wrong. Otherwise, the function will provide the updated venue object.

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Add a DAL function in the Venue API.

The function will delete the file from Firebase Storage and update the venue object, setting the value for the marker to null.

The response will fire an error if something goes wrong.