Update IMDv3 support details for GROMACS, NAMD, and LAMMPS

[orbeckst]

Related to MDAnalysis/mdanalysis#4923

Changes made in this Pull Request:

• state for each engine if they support concurrent connections
• minor markup/link reformatting
• moved information from feature: IMDReader Integration MDAnalysis/mdanalysis#4923 to here

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.93%. Comparing base (07069e1) to head (1e854a9).

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[ljwoods2]

We've never tested multiple connections to the same port, so might be worth mentioning this is essentially undefined behavior. For example, when changing waiting behavior, does one client's requested change affect all others? If one client disconnects, does the simulation pause as long as at least one other client is connected?

[orbeckst]

Good points! Where should we write this in the docs @ljwoods2 ?

[ljwoods2]

Maybe just include the information in-line like this?

[orbeckst]

Thanks @ljwoods2 !