Factorize business logic and new features for censored data

Modify the two files with the functions for the Shiny app:

• ssd_logic.Rmd
• ssd_code_generation.Rmd specifically for generating code for the user. Work in progress. Will be greatly modified when the functions in the main Rmd file will become accessible to the user

Additionally, create two lab notebooks reflecting on specific aspects of the application:

• comb_plot_options.Rmd checking if the different plot options can be applied on top of one another
• cens_data.Rmd exploring the possibilities of censored data. The work has since been integrated to the ssd_logic.Rmd file.

Closes #2 (closed)