Invert default schema URLs

[mferrera]

As part of schema versioning the default schema URL was changed to 'dev', such that an explicit 'prod' schema would be produced. However, this would also mean that during metadata generation the default URL would be the 'dev' url, which is clearly not correct. This should be handled differently

[mferrera]

A related but separate feature is that it would also be desirable to dump 'dev' data and validate against the 'dev' schema in certain contexts (e.g. Komodo). This is happening now, which is good, but we currently lack a reasonable way of switching it up in production.