API/DAO Metadata - Retain versioning metadata for possible usage in runtime+tooling

[totten]

Overview

This is an excerpt from #17729. It makes available more metadata to indicate when fields were created.

Before

In xml/schema/**, there is information about when fields were created. However, this information is not passed through to the DAOs - so it cannot be presented at runtime.

After

The metadata is part of the DAO's fields() tree.

Comments

I extracted this from #17729 because (a) this part is large and prone to growing stale and (b) there are a few different things going on in the original PR, and it may take a bit longer to sort the functional changes. However, this part seems like very low-hanging fruit.

Additionally, the metadata may have multiple uses (e.g. improving the docs which are built into the API Explorer).

[civibot]

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[colemanw]

This doesn't do anything by itself, it's practically a NFC. Should be safe to merge on pass.