Add nonparametric circadian rhythm analysis (NPCRA) functions

[danielvartan]

Comments in English, Spanish, or Portuguese are welcome.
Comentarios en inglés, español o portugués son bienvenidos.
Comentários em inglês, espanhol ou português são bem-vindos.

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Instructions

• Create a branch called feature/npcra.
• See all the references in the basic references section before starting the development.
• The function must take an object of class tsibble (mandatory).
• Create one function for each NPCRA parameter.
• Create special functions that allows the user to set the interval windows (e.g., the user may want a M5, M12 function, not only a M10 function).
• The functions must include all methods of calculation presented in ActStudio.
• Add a vignette, with practical examples, explaining the features.
• All exported functions must be fully documented.
• All functions must be accompanied by unit tests (100% coverage).
• References in the documentation must be formatted in accordance with the APA (American Psychological Association) manual.
• When finished, crate a PR to the main branch. Don't forget to mention this issue when creating your PR.

Materials

• Actigraphy log.
• Guidelines for Contributing.

Basic references

• Gonçalves, B. S. B., Cavalcanti, P. R., Tavares, G. R., Campos, T. F., & Araujo, J. F. (2014). Nonparametric methods in actigraphy: an update. Sleep Science, 7(3), 158-164. https://doi.org/10.1016/j.slsci.2014.09.013
• Gonçalves, B. S. B., Adamowicz, T., Louzada, F. M., Moreno, C. R., & Araujo, J. F. (2015). A fresh look at the use of nonparametric analysis in actimetry. Sleep Medicine Reviews, 20, 84-91. https://doi.org/10.1016/j.smrv.2014.06.002
• Witting, W., Kwa, I. H., Eikelenboom, P., Mirmiran, M., & Swaab, D. F. (1990). Alterations in the circadian rest-activity rhythm in aging and Alzheimer's disease. Biological Psychiatry, 27(6), 563-572. https://doi.org/10.1016/0006-3223(90)90523-5

Other references

• American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.).
  https://doi.org/10.1037/0000165-000