ENH: Add function for peak picking

[VinzentRisch]

Chromatographic peak detection for high resolution LC/MS data in centroid mode.

Uses the readMSData() function to import data into an XCMSExperiment object and the findChromPeaks() function (centWave algorithm) for peak picking. Both functions are from the R package XCMS.

Outputs a XCMSExperiment artifact that can be exported and imported into R with the package MsIO.

Metadata can be used to label samples (blanks, QC samples …).