Design for refactor of integration guide [BD-3156]

We have several thoughts re: improving the navigation experience of the devhub (this is based on brainstorming with Eric/Ed/Rachel):

1. In the devhub hierarchy, the current section called “Developers Guide” needs a different title… Current thoughts are “Blockchain Developers”. (Because pretty much everyone using the devhub is a developer-- need to identify different user types, distinguishing integrators from those making changes to the protocol itself.)

2. Usability would be improved by changing the landing page (FIO Developer Portal (fioprotocol.io)) to be more user oriented. So, buttons for Exchange Integrators, Wallet Integrators, FIO Blockchain Developers, <others>? And possibly one button leading to reference information useful for anyone like the API…but generally focusing on distinct user types.

3. Break out the current devhub page into separate pages… Integrators, and a separate page for Blockchain Developers.

4. Create links for each separate devhub page in the top horizontal menu (replacing Documentation).

5. Reorganize the Integration portion… FIO Overview and FIO chain information, then break out Wallet Integration, Exchange Integration, <future NFT Integration> with their own sections.

(I think these changes would make a big difference in terms of information design/usability… feel free to throw darts at will!)