[SHIRO-838] create sha512 and sha3-512 hashes.

[bmarwell]

Create .sha512 and .sha3512 files as required by Apache Infra.

The new download page (using jbake + yaml) can later be configured to have a list of boolean fields in a "checksum" object like this:

shiro190:
  checksums:
    sha3512: true
    sha512: true

(we can play with the defaults just in case).
This way we can link the appropriate hashes automatically.

---

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[bmarwell]

Needs to be cherry-picked into main.