serofoi 0.0.9

This release of serofoi, includes the following:

1. Implementation of package modules: Incorporates data preparation, modeling, and visualization modules, they enable efficient handling of data, perform statistical modeling, and generate visual representations of the results.
2. Documentation: It consists of vignettes, a website, and uses cases that provide detailed instructions on how to use the package effectively.
3. Implementation of 3 models for calculating the Force-of-Infection (FoI): The first model is the constant or endemic model, which assumes a stable FoI over time. The second and third models are time-varying, with the normal FoI model representing a slow change in FoI and the normal-log FoI model representing a fast epidemic change in FoI.
4. Definition of coverage test to assurance the quality of the package.

Overall, this release introduces essential package functionality, comprehensive documentation, various FoI models, and a coverage test, enabling users to analyze seroprevalence data and calculate the Force-of-infection.