Remove REAX and MEAM packages

[akohlmey]

Purpose

This pull request fixes #1129 by implementing the changes listed in the issue and removing the MEAM and REAX packages from LAMMPS. The packages were discouraged from use for a while already.

Author(s)

Axel Kohlmeyer (Temple U)

Backward Compatibility

Inputs with pair_style reax commands will be given a message pointing out the last LAMMPS version that contained this pair style. They need to change the syntax to accommodate the pair_style reax/c syntax (and have to have the USER-REAXC package installed). Inputs with pair_style meam commands will be redirected transparently to the pair_style meam/c, provided the USER-MEAMC package is installed.

Implementation Notes

For details, please see issue #1129

Post Submission Checklist

Please check the fields below as they are completed

• The feature or features in this pull request is complete
• Suitable new documentation files and/or updates to the existing docs are included
• One or more example input decks are included
• The source code follows the LAMMPS formatting guidelines

[athomps]

I approve this change.

[akohlmey]

not sure why i had to trigger the rebuild multiple times and only the merge conflict resolve did the trick to have the rebuild work without a failure and also handle the merge conflict. 👎

[rbberger]

@akohlmey applied some new settings to the PR builder. That should avoid this issue.