Remove Iv core Op in favor of Ive and add rewrite rule for log of it

[ricardoV94]

Description

Similarly to how we approached Kv/Kve in #1081, we only need one core Op: Ive.

We should include the equivalent log(iv(x)) rewrite for stability, where iv is the expression based on ive returned by the helper.

The goal is to have one canonical form and reduce the number of Ops we need to test/support.

[AdvH039]

Hey @ricardoV94, for this issue I followed the PR for kv and I expressed iv in the form of a ive helper as iv(v,z) = ive(v,z) * exp(z), but it overflows for iv(v,z) when z>100 for v=4.5 that is around 1e36 which I don't think should be happening.
Please let me know where I'm going wrong. Thanks!