Replace ` /` with `_` in the name column in pData and flowworkspace_summary

[ppreshant]

in get_and_parse_plate_layout() : I added the / to between assay_variable and sample_category but don't recall the reason for making this new column when the sample_name_bulk already has a _ delimiter?

Am later replacing the / with _ with str_replace while renaming fcs files before write.FCS() in 7-exploratory..R for saving aggregated data from multiple runs/plates`