Solution for fast index lookup from string

[MichaelHuth]

We could use a faster solution for a generic index lookups based on strings.

We use that on key locations in MIES such as the Wave Cache and the Labnotebook.

Could be wrapped in an XOP with a suitable API, shared R/W mutex.

If the keys are stored sorted then the lookup can use binary search that uses only O(log N).

[t-b]

If we go for the XOP, let's use the fastest hashmap from https://martin.ankerl.com/2022/08/27/hashmap-bench-01/.

[t-b]

Relevant prior investigation: https://www.wavemetrics.com/forum/general/brief-performance-review-key-value-store-methods-igor-pro

keyvalue-store-benchmark_with_hashmap.zip