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

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