Enable SFCGAL in FMTM database for additional PostGIS functions

[spwoodcock]

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Describe this PR

• This was much simpler than anticipated.
• Simply enabled the sfcgdal extension via a migration (it's already baked into the postgis img, with the right version we need!)
• Prep for the call about fmtm-splitter tomorrow.
• PostGIS ❤️

Review Guide

Notes for the reviewer. How to test this change?

Checklist before requesting a review

• 📖 Read the FMTM Contributing Guide: https://github.com/hotosm/fmtm/blob/main/CONTRIBUTING.md
• 📖 Read the HOT Code of Conduct: https://docs.hotosm.org/code-of-conduct
• 👷‍♀️ Create small PRs. In most cases, this will be possible.
• ✅ Provide tests for your changes.
• 📝 Use descriptive commit messages.
• 📗 Update any related documentation and include any relevant screenshots.

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