Add KNITRO persistent solver

[eminyouskn]

Fixes NA

Summary/Motivation

This PR adds a persistent solver implementation for KNITRO.

Changes proposed in this PR

• New persistent solver implementation for KNITRO that supports incremental addition of variables and constraints
• Limitations of this implementation:
  • Does not support removal or modification of variables, constraints, or parameters (KNITRO itself does not support removal operations)
  • Does not automatically detect which components have been added or removed

Legal Acknowledgement

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1. I agree my contributions are submitted under the BSD license.
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[mrmundt]

Is there a reason that you are taking this out of base? It seems like it makes more sense here.

[eminyouskn]

I moved it because the config of the persistent interface needs to inherit from the PersistentSolverConfig and the direct interface needs to not inherit from that class. So I moved the typehint to each implementation.