feat(mrf): add static workflow routing

[wanlingt]

Problem

We want to add static routing to MRF

Closes FRM-1577

Solution

This PR allows static routing for steps 2 and 3 of the workflow. It emails the respective respondent when the form has been submitted at each step.

Backend

• Add workflowStep property to the submission schema.
• Add workflow property to the form schema. This is an array of objects, where each object contains the workflow_type and emails. More properties (e.g. form field IDs) can be added in the future.
• Trigger MRF email to be sent to the email addresses saved in the form's workflow step

Frontend

• Add workflow settings tab to the settings page

Breaking Changes

• No - this PR is backwards compatible

Features

Before & After Screenshots

AFTER:

Tests

• Create an MRF form
• In the form's settings, navigate to the workflow tab
• Key in an email address in respondent 2 and respondent 3's email inputs
• Submit the MRF form once
• The email address associated with respondent 2 should receive an email asking them to fill in the form
• Click the link in the form, you should be brought to the unlocked MRF form
• Submit the form
• Repeat the steps for respondent 3, submit the form
• Respondent 3's response should be reflected in the form's results page

[linear]

FRM-1577 3-respondent static workflow

[KenLSM]

What are these form fields to be added?

[wanlingt]

These form fields refer to the next stage of static routing, where we specify which fields the respondent should fill in. I'll remove it haha (053fd8d), it might be confusing. And whoever works on it next should be able to figure it out anyway!

[KenLSM]

/nit For discussion, non-blocking

I recall that we have logs disabled for middlewares, i.e., makes debugging difficult

[KenLSM]

LGTM aside from the question on form fields