Option to impute missing sleeplog entries for sleep onset and wakeup time

[vincentvanhees]

Adds option to impute sleeplog entries for onset and wakeup time with the median of the values on the remaining days. Fixes #1088

Checklist before merging:

• [ ] Existing tests still work (check by running the test suite, e.g. from RStudio).
• [x] Added tests (if you added functionality) or fixed existing test (if you fixed a bug).
• [x] Clean code has been attempted, e.g. intuitive object names and no code redundancy.
• [x] Documentation updated:
  • [x] Function documentation
  • [ ] Chapter vignettes for GitHub IO
  • [x] Vignettes for CRAN
• [x] Corresponding issue tagged in PR message. If no issue exist, please create an issue and tag it.
• [x] Updated release notes in inst/NEWS.Rd with a user-readable summary. Please, include references to relevant issues or PR discussions.
• [ ] Added your name to the contributors lists in the DESCRIPTION file, if you think you made a significant contribution.
• [x] GGIR parameters were added/removed. If yes, please also complete checklist below.

If NEW GGIR parameter(s) were added then these NEW parameter(s) are :

• [x] documented in man/GGIR.Rd
• [x] included with a default in R/load_params.R
• [x] included with value class check in R/check_params.R
• [x] included in table of vignettes/GGIRParameters.Rmd with references to the GGIR parts the parameter is used in.
• [x] mentioned in NEWS.Rd as NEW parameter

If GGIR parameter(s) were deprecated these parameter(s) are:

• [ ] documented as deprecated in man/GGIR.Rd
• [ ] removed from R/load_params.R
• [ ] removed from R/check_params.R
• [ ] removed from table in vignettes/GGIRParameters.Rmd
• [ ] mentioned as deprecated parameter in NEWS.Rd
• [ ] added to the list in R/extract_params.R with deprecated parameters such that these do not produce warnings when found in old config.csv files.

[vincentvanhees]

Thanks, I have been reflecting on this and think it is better to cancel this effort and instead expect GGIR users who want this to take care of sleep diary imputation outside GGIR.

Motivation: Accounting for weekday requires access to day of the week which the basic sleep log does not offer, which then forces us to retrieve this by matching with accelerometer data. This significantly increases code complexity. Further, I designed GGIR to intentionally exclude nights when sleep diary data is not complete, because there is no evidence that combining guiders (sleeplog and HDCZA) or imputing guiders truly provides meaningful estimates of sleep.