Add put + get with multiple keys *and* versions

[fm3]

• New APIs GetMultipleKeysByListWithMultipleVersions and PutMultipleKeysWithMultipleVersions
• ListKeys now supports optional prefix field
• Bump dependencies (scala to 2.13.15, rocksdbjni to 9.4.0, scalapb to 0.11.15)

Issues

• contributes to Multi-Get and Multi-Put with list of keys #39

TODO

• should multi-put assert no duplicates? → no
• should we also implement GetMultipleKeysByList to return just one version? (technically you could set hightest and lowest to the same value and reach the same output, but kinda weird) → that’s ok for now, add it when needed.
• implement optional prefix for listKeys
• changelog