Extend pca() arguments to allow specifying BPPARAM in the calls to BiocSingular

[trinetra75]

Looking at the pca() code I noticed that the function does not have a BPPARAM parameter as it happens to have the BiocSingular::runSVD() function and that allows usage of multi-core algorithms where applicable...

Would it be possible to add it to this function (it is already a parameter of the function parallelPCA())? In case I would be perfectly happy to do the heavy lifting if someone gives me some feedback (in a pull request)

Thanks.