[FEA] Support concurrent insert/find for static_map when size of K-V pair is greater than 8 bytes

[chirayuG-nvidia]

An optimized implementation of string renumbering in cuGraph requires building histogram with metadata along with frequency as the payload. The metadata is required for optimal performance of subsequent operations in the renumbering implementation. CUDA kernel concurrently finds/inserts the data in HT.

Since CuCollection currently doesn't support concurrent insert/find for more than 8 byte KV pair size, we currently cuDF concurrent_unordered_map with some manual checking to check update of payload values.

It would be great if CuCo supports concurrent find/insert on complex payloads for static_map.