Implementing multistart version of theta_est using multiple sampling methods

[sscini]

Fixes # .

Summary/Motivation:

Currently, the optimization is only done from a single initial value. This implementation adds the ability to specify multiple initial values using selected sampling techniques: from a random uniform distribution, using Latin Hypercube Sampling, or using Sobol Quasi-Monte Carlo sampling.

Changes proposed in this PR:

• All changes made adding pseudocode in comments
• Added inputs needed for multistart simulation
• Added a function to generate points using the selected method
• Added theta_est_multistart to work for the multistart process

TODO before converting from draft:

• Receive feedback from collaborators on logical setup
• Convert finalized pseudocode
• Test and debug
• Confirm function with examples

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[sscini]

@djlaky @adowling2 Please provide early feedback.