Move all external dependencies on Google spreadsheets to Github

[TjWallas]

Github flavored markdown facilitates the creation of tables, among other forms of content. To have all material and its dependencies in one place and forester collaboration via Git, it would be better to migrate the Google spreadsheets (listed in Related Material section of the README) to Github in the form of markdown documents. For now, even exporting them as CSV files could be useful :)

The rationale behind this is that the related material section is more or less metadata regarding the material presented here and could even be used as an index to navigate the problems and solutions here. Decoupling this from the repository confuses the first-time developer who lands here.

[AhmadElsagheer]

That will be major change for two reasons:

1. Google spreadsheets are more controllable than markdown tables. For example, no merge or coloring options.
2. Some of the spreadsheets are active training sheets that are regularly edited by participants. Google spreadsheets offer range protection and that makes it easier than github commits for all sheet participants. In addition, they can comment for help with their codes and stuff related to the training which will not be a good idea if done with github issues

What do you recommend?