Optimal Hard Thresholding to determine encoding dimension

[andrearaithel]

Estimation of the optimal encoding dimension q based on the sample size in the estimateBestQ function is replaced by the OHT procedure. It provides a faster alternative to the findEncodingDim function.

• move estimateBestQ from helperFunctions.R to controlForConfounders.R
• replace estimation formula by deterministic OHT procedure
• add pracma and RMTstat package to Imports
• add denoiseR package to Suggests
• add unit tests
• add OHT reference to bibliography
• update vignette

[AtaJadidAhari]

Some tests might need to be updated as ee5ee2e resulted in an error in test.