[C++] Build core compute kernels unconditionally

[benibus]

Describe the enhancement requested

From #25025

Since we are going to implement a lot more precompiled kernels, I am not sure it makes sense to require all of them to be compiled unconditionally just to get access to compute::Cast, which is needed in many different contexts.

This would entail building a small subset of kernels into libarrow by default. The remaining kernels could be conditionally included via cmake options.

Component(s)

C++