Issue #2876085 by heddn, maxocub, phenaproxima, Jo Fitzgerald, vasi, quietone, yoroy, masipila, larowlan, neclimdul, krystalcode, catch: Before upgrading, audit for potential ID conflicts

Issue #2917883 by quietone, TR, Jo Fitzgerald, masipila, phenaproxima: Rename 'migration_templates' directories in core modules to 'migrations'