[HiTL] Migrate off Heroku to EC2 of Mephisto

## Type of Issue

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- [ ] Bug report (to report a bug)
- [ ] Feature request (to request an additional feature)
- [ ] Tracker (I am just using this as a tracker)
- [ ] Refactor request
- [ ] Documentation Ask

## Description

This is a high priority task since Mephisto requires us to migrate off Heroku ASAP. It's supposed to be easy enough if we pull the latest Mephisto and use the script to migrate. However, a relevant newer version of Mephisto is not compatible with our HiTL scripts (that's why we are using a older, more stable version of Mephisto), which need to be addressed.

## Current Behavior

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## Expected Behavior

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## Steps to reproduce

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## Links to any relevant pastes or documents

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## Checklist

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- [ ] Task 1
- [ ] Task 2
- [ ] Task 3 ...