making use of endf.get_evaluations

[shimwell]

Description

making use of endf.get_evaluations from the endf-python package made by paul. this continue the theme of saving a few lines and reducing duplication. endf-python is already a dependency.

let me know if these PR are too small just for future reference.

Fixes # (issue)

Checklist

• I have performed a self-review of my own code

• I have followed the style guidelines for Python source files (if applicable)

[GuySten]

The endf package use Material object which is not identical to the Evaluation object that openmc use (at least the name is different).
I think this change will be ok only if we move the Evaluation object to the endf package.

[shimwell]

What do you think @paulromano

Here is a link to the get_material function in endf which is the same content but different name to the get_evaluations over here in openmc world.

https://github.com/paulromano/endf-python/blob/7bf0f8c1ced3c42bee8e0f6f2ce9182fa9b1041a/src/endf/material.py#L265-L289

We could adopt the endf-python standard and rename any use of get_evaluations to get_materials across the openmc codebase as part of this PR?

[paulromano]

Thanks @shimwell!