Remove babel loop

What does this MR do?

This MR is a sub MR of !19 (merged) which has been stalling for a while, and can't be merged easily now that we upgraded to Babel 7. The idea here is to scope discussions on removing the Babel loop introduced in the meantime.

Initial postulate: Babel 7 doesn't preserve file paths anymore. As a workaround, we leverage the --relative param which creates a folder relatively to the file compiled.

Example: ./example/index.js will be compiled to ./example/out/index.js if the output dir is set to out,

This change will avoid collisions when filenames are the same, even in different folders. The files generated are cleaned-up after the analyzer has run.

What are the relevant issue numbers?

#35609

Does this MR meet the acceptance criteria?

• [-] Changelog entry added
• [-] Documentation created/updated for GitLab EE, if necessary
• [-] Documentation created/updated for this project, if necessary
• [-] Documentation reviewed by technical writer or follow-up review issue created
• [-] Tests added for this feature/bug
• [-] Job definition updated, if necessary
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• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer