Change the examples folder into docs examples

[ChrisRackauckas]

This would make them a lot more visible, able to show visuals, and would make them tested as part of the doctests. We'd just need to set strict mode, i.e. just like https://github.com/SciML/DiffEqFlux.jl/pull/721/files#diff-4aae2d1c783cade58bd2cb13748da956e568b7f2aed5fafd9e2a46fb97daf613R14-R21 . @Abhishek-1Bhatt can you give an attempt at this?