task/INBA-766-PO-export-flags - Added functionality to download flags and other project data as a zip file

[Perry5]

What does this PR do:

• Adds feature to create separate csv for flags
• Zips both csv's up and sends to the client for download

To Test:

• Create a project, survey, assign task, complete task etc.
• Download the csv from the client
• You should get a zip file containing two csv's- one for the project data and one for just flags

Make sure you have feature/inba-765-jf-export running on the front end if it hasn't been merged as well as feature/ser-29-get-answers-by-question-number on the surveyService

[sirctseb]

@Perry5 it won't let me add you as a reviewer but please review, I added a commit to deduplicate the discussion export (see my review comment)