Retroactive/historical `TTLStrategy` and `activeDeadlineSeconds`

# Summary

Currently you can set `activeDeadlineSeconds` and `ttlStrategy` on a per workflow basis, or as a default. But neither apply retroactively.

# Motivation

So we can clean-up historical workflows automatically, reducing operating costs.

# Proposal

For new workflows we can apply them automatically when we set-up defaults.

For historical workflows, we can't do `activeDeadlineSeconds`. This is applied to pods when they are created.

For historical workflows, we already have an TTL informer that will delete them. What we could do is when that informer starts, if they are missing the value, and we think they should have it, we patch them.

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**Message from the maintainers**:

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Start with the existing TTL informer and the handling of TTLStrategy and activeDeadlineSeconds. Determine how defaults identify historical workflows that are missing values; done means eligible workflows are patched for TTL cleanup while activeDeadlineSeconds remains limited to newly created pods, with tests covering the behavior.

Written by the indexing model from the issue text.