small modifications to support 2 things. 1) fetching domains parameters ...

Hello foreman crew, thanks for all the work you all have put into this system. My colleague and I are making extensive use of it. One of our primary use cases is the external node classifier where we can maintain application configuration data for different environments (modeled as foreman domains).

This requires maintaining a lot of domain parameters, and as such I wanted two things that weren't supported.

1) programmatic access to domain parameters for scripted crud/copy operations. This is what the change to the domains controller did for me.

2) display sort order of existing domain parameters on the edit form so it's easier to scroll through the list to find what I'm interested in. This is what the changes to the domain model and involved views did for me.

It may not be a priority for you all, but the changes are mostly cosmetic and I think would be nice to have in the distribution. It is worth noting that I did this work directly on our installed copy of 1.1-stable, so this diff should backport into those versions without issue. It is also worth noting that I haven't tested this change on any newer versions of foreman, so those of you with more knowledge than me should of course audit whether or not this is the best way to solve the problem.