Add FAQ Section to Docs

[pulsipher]

Following #213, we should had a FAQ page in the documentation that addresses a number of common questions that common in domain specific areas (e.g., optimal control).

It might also be a good idea to create a terminology table to equate domain specific terms to our unifying abstraction.

[SalmanRashid1979]

Hi @pulsipher I am a technical writer looking to contribute to open source projects on GitHub. I am new to Github and was wondering if you'd like my help with this. Give me a shout if you do 😊

[pulsipher]

Pull requests are more than welcome. Please review our docs on contributing to learn more: https://pulsipher.github.io/InfiniteOpt.jl/stable/develop/start_guide/.

For the particulars of this addition, I can jot down some FAQs later as a starting point. Note, I foresee this following a tutorial type format so it will require familiarity with the API and existing documentation.