Changes to ARKitecture page (pt. 1)

[sidd3888]

• Capitalize ARK in Econ-ARK in two instances in the beginning of the page
• We planned on recommending either PyCharm or VSCode as part of our new installation guide right? It might be confusing then to mention Spyder as our recommended editor on this page.
• The CRRAutility() does not exist in the HARK.utilities module anymore, and has been moved to the HARK.rewards module in the latest version and as per the API reference
• The increased set of tool modules need to be referenced in the ARKitecture documentation and current descriptions updated, such as utility functions being moved to rewards or the closest to approxLognormal() now being approx_lognormal_gauss_hermite()

Will add more to this after understanding some of the objects in HARK better

@MridulS please let me know if there is already some work in progress on this like last time or any technical inputs