Serverless function for File Download process

[AndyRae]

A serverless function for generating rule files.

• [x] New function: RulesFileSave ??
• [x] Queue trigger
• [x] Takes below dict as arguments
• [x] Move mapping rules service to shared
• [x] Generates rules based on the arguments
• [x] Saves file to storage
• [x] Creates the File Download db entity

Args:

scan_report_id
user_id
file_type