Experiments on numeric arrays

[fm3]

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

• abc

Issues:

• #3810

---

(Please delete unneeded items, merge only when none are left open)

• [ ] Updated (unreleased) changelog
• [ ] Updated (unreleased) migration guide if applicable
• [ ] Updated documentation if applicable
• [ ] Adapted wk-connect if datastore API changes
• [ ] Adapted wk-libs python client if relevant API parts change
• [ ] Needs datastore update after deployment
• [ ] Ready for review

[fm3]

more ideas:

accessor/iterator methods for the byte arrays, yielding Longs (for equality checks) or UnsignedIntegers.

Make the UnsignedInteger for this iterator mutable, thus avoiding re-allocating?