Neutrino component - #18809

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@nstarman If the total component gets merged. I will work on the docs and changes and changes.

@nstarman This is now a different milestone ? I think it might be finally ready for a review and a merge. Have a bit more time in the coming weeks will help you this forward.

@preshanth can you rebase and change the whatsnew to 8.0.rst ?

@nstarman working on it. Some docstests are failing after rebase. Will fix and push. Only check when I mark this as ready for review

@nstarman I could use a suggestion of which way to go. The _nu_info method I think should be an abstract method in the trait. Then I want to move the _nu_info into a method inside flrw and then I can show a real custom neutrino cosmology. Currently that is not that case. Do you think that makes sense to you. If you say yes I will go ahead and implement that.
I have rebased and fixed the whatsnew issue. Just was realizing that the docs examples don't really show an actual neutrino component trait.

@nstarman I rebased and did a bit more than what I was planning. Cause it was annoying me. Have a look at neutrino.py I introduced another private class there made the neutrinos more trait like and independent. I also showed an FLRW like class in the docs as an example.

Sorry. Recently merged PRs mean you rebase to rebase this one.

@nstarman Hopefully one last review. I hope I got all the rebasing right.

Thanks for the assist.

@preshanth we have this group if you're interested: https://github.com/orgs/astropy/teams/astropy-contributors

@nstarman That sounds good. I can't access it however is giving me a 404.