DISC: Support two modes of operation (READABLE, COMPILED)

[mmcky]

It might be possible to support two primary modes of operation:

READABLE: This would compile notebooks that are as simple as possible, making use of markdown and rendering markdown based tables, figure inclusions etc. This is more limited as markdown does not support all features of RST

COMPILED: This would place an emphasis on compiled output which would allow for less readable jupyter notebooks in favour of supporting more features of RST+HTML which could provide for feature filled notebooks. Given this tool is built as a tool to compile between RST and IPYNB this would be most fit for the default.

[mmcky]

ipynb based translator will focus on readability and notebook production, while html will target more html rich data structures when writing notebook.