#163187158 Consume api endpoint to create red-flag and intervention reports

[valenstical]

What does this PR do? This PR connects the create report page with the corresponding api endpoint for the user to create a new red-flag or intervention report from the user interface.

Description of tasks

• Use vanilla Javascript Fetch API to make requests to POST/ api/v1/red-flags and POST /api/v1/interventions endpoint to create a red-flag or intervention report respectively

How can this PR be tested

• Visit https://valenstical.github.io/ireporter/sign-in.html to sign in. Use username: demo and password: 123 as sign in credentials if you have not created an account yet.
• Click on the dropdown menu on the far right, click on 'Create report'
• Enter the report details and click on 'Submit report'

What are the relevant pivotal tracker stories? #163187158

Screenshot