While performing some performance testing for one of my projects, I saw that in case of creating many (a lot of) CEL programs in the same environment, creation of function bindings for them can take a significant percentage of CPU time, because they are being regenerated on every program creation, which, as I can see from code, feels really excessive. This PR suggest a way to perform calculation of bindings once for environment configuration and then reuse this bindings in program creation.

Probably, there also should be provided a way to change this behavior through options, let me know if that feels more acceptable with them.

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