Move element distribution code from DgElementArray to free function

[nilsdeppe]

Proposed changes

I'll need to share this with the nodegroup code.

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Further comments

[knelli2]

Is formatting really ok with this space in the function call?

[nilsdeppe]

I'm not exactly sure what you mean by "okay". Clang format doesn't remove single blank lines (it does combine multiple blank lines into one!) and I found it easier to read the function call separating the slew of size_ts that represent hardware things from the parts that are tied to the element info 🤷

[knelli2]

Hmm do we have a convention for this? I think there are many other instances of function calls that have a bajillion parameters that are difficult to read. Some have comments between lines to make it easier, some don't. Not gonna hold up this PR though, but we should probably figure out what to do

[knelli2]

Hmm do we have a convention for this? I think there are many other instances of function calls that have a bajillion parameters that are difficult to read. Some have comments between lines to make it easier, some don't. Not gonna hold up this PR though, but we should probably figure out what to do