Add active sampling capability within desirable feature and target region

[danielchen26]

The code changes include the addition of a new file, distancebased_active.jl, which allows for setting up desirable_range for active feature constraints, and target_constraints active searching in the dimensional target space.

The rationale behind these changes is to enhance the generative design process by incorporating active sampling, which enables the selection of samples from desirable regions of the feature space and target region. This allows for a more targeted and effective exploration of the design space, leading to improved results in the generative design process. The addition of active sampling capabilities in the GenerativeDesigns module addresses the need for more efficient and focused exploration of the design space, ultimately improving the quality and performance of generative designs.

[thevolatilebit]

@danielchen26, I suggest adding a paragraph or two on the background of active sampling, including some references. Additionally, as a style tip, I recommend using backticks to highlight names of variables, etc., in the tutorials.

[thevolatilebit]

Thank you!