Old style assets should be rejected at upload

[busma13]

While looking into another issue (#3653) I was looking at the assets used in e2e tests. They are the old style that is both non-bundled and has processors, schemas, etc in one index.js file. These assets no longer work with teraslice v2.0.0 because the operation-loader fails when it tries to require processor.[js/cjs/mjs].

We should add a check at asset upload to check for and reject these older assets instead of waiting for a failure when we register a job that uses the asset.

[busma13]

I didn't find a reliable way to differentiate between asset styles that wasn't slow. The only way I could come up with was to look for a processor.js or schema.js, but these files can be deep in the file tree, which took some time to find.