Replace manager frontend PWA with mapper frontend PWA

[spwoodcock]

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

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

Related Issue

Fixes #1567

Describe this PR

• This was tricky previously due to /mapnow subpath for the mapper frontend.
• The setup was tweaked to use a subdomain instead mapper.fmtm...
• Now the PWA should be installable and work as intended.

Review Guide

• Visit https://mapper.dev.fmtm.hotosm.org
• Can the PWA be installed via chrome?

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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