IS migration improvement

[nicholaspcr]

Summary

Counterpart of https://github.com/TheThingsIndustries/lorawan-stack/pull/4418

Changes

• Update migrations to only be considered applied after they are successful.
• Update migrations names to have .tx.(up|down).sql as its new suffix, forcing them to run in a transaction.

Testing

Steps

Initialised the database using tools/bin/mage dev:dbStart dev:initMTStack and there are no errors.

Regressions

This PR changes the logic of what is considered a successful migration but it should not have an impact on the contents of any migration.

Notes for Reviewers

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Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.