The new tidy sccomp interface

We announce the new tidy and modular interface for a sccomp, which improves modularity, and clarity. The main change is the modularisation of sccomp in functions which can be linked with the pipe operator |>. Function Description Estimation: sccomp_stimate() which is usually run once in the analysis (per model). Testing: sccomp_test() which candy run multiple times, depending on how many contrasts you want to test (e.g. age, untreated vs treated).