Move content from tudat-space to tudat-developer-docs

[FilippoOggionni]

The content of this directory (developer tools) should be moved to the developer docs.

To summarize for simplicity, the main topics of these guides are:

• CMake
• Advanced conda usage
• Developing with CLion
• Conda-smithy
• Advanced github
• Developer environment (e.g., tudat-bundle)

We should check if these information are already present in the developer docs; in that case, they can be merged or removed altogether. I am quite sure that for the developer environment there are some info on the tudat-developer docs, but also in this README (perhaps it should be updated).

For the remaining bullet points,@ggarrett13, I think you have the best overview of the tudat-developer website, what should go in there and what is already in there. If you can have a look and let me know which rst files of the directory linked above should be kept/merged/ and where you would like them to be, I can take care of moving them and adapting the content.