sort files into proper folder structure

[BHboaz]

Deliverables

• rename certain files so it is clear what is in them
• make sure new files are rightly structured
• put source code files where they belong (proper module in src)
• decide which format to use for source code file s(e.g., downloading data should be an .R file, not .Rmd)
• put makefile in right folder

[BHboaz]

sort files into proper folder structure, see https://tilburgsciencehub.com/structure/project-setup/?utm_campaign=referral-short