Moving mpibind to the allocation modifier

Configuring mpibind requires setting scheduler flags that are handled by the allocation modifier. Rather than creating a separate modifier for mpibind, its functionality can instead be moved to the allocation modifier itself.
Requires follow up work to the archived PR #646

Start by reviewing archived PR #646, then inspect the allocation modifier and the existing mpibind modifier to compare the scheduler flags they handle. Done means mpibind configuration is handled by the allocation modifier without a separate modifier; the issue names no files or tests to run.

Written by the indexing model from the issue text.