Draft: Remove `Engineering Backend EM` job family in favor of `Development EM` job family

Why is this change being made?

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This branch illustrates that most of the content in Engineering BE EM is a duplicate of Development EM. IMO it looks like we should remove Engineering BE EM entirely, given:

1. the high amount of overlap with Development EM
2. the overhead/inefficiency in maintaining 2 job families that are almost identical
3. the fact the Development EM role was consolidated already with !288 (merged).

Thanks @mnohr for bringing my attention to this in !4573 (comment 1834107714)

Author and Reviewer Checklist

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Commits

• Remove description shared with Development EM role
• Remove nice-to-haves shared with Development EM role
• Remove requirements shared with Development EM role
• Remove responsibilities shared with Development EM role

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