refactor(env-vars): check env vars in production for migration

[naftis]

#5932

Refactors migration to enforce setting environment variables in production. Doesn't use envalid to keep things simple.

NOTE!: Also adds a set -e to run-migrations.sh to fail the whole script if any of the commands fails. I thought this is necessary for example in the case of reindexing search, if the Mongo migrations fail, the ElasticSearch gets bad data also.

[github-actions]

Oops! Looks like you forgot to update the changelog. When updating CHANGELOG.md, please consider the following:

• Changelog is read by country implementors who might not always be familiar with all technical details of OpenCRVS. Keep language high-level, user friendly and avoid technical references to internals.
• Answer "What's new?", "Why was the change made?" and "Why should I care?" for each change.
• If it's a breaking change, include a migration guide answering "What do I need to do to upgrade?".

[ocrvs-bot]

Your environment is deployed to https://ocrvs-5932-migration.opencrvs.dev.