refactor: move url encoder from rest catalog to util for common use

[WZhuo]

The url encode and decode function will be used for generating partitions' path, so move it to the common util for later use.

[wgtmac]

Can we avoid adding cpr to the core iceberg library? Why is it needed to generate partition path?

[WZhuo]

Result<std::string>  LocationProvider::NewDataLocation(const PartitionSpec& spec,
                                              const PartitionValues& partition_data,
                                              const std::string& filename) = 0;

In LocationProvider::NewDataLocation, we must do url encoding for partition names and partition values.
If not import cpr to iceberg core, maybe we need implement Url encode/decode by ourselves.

[wgtmac]

Got it. According to prior discussions in the community, we should keep minimal dependencies of libiceberg. If the only reason is to escape partition path, should we implement our own utility function? IIUC, partition name and value can only use a limited set of characters.