`cbind`: unique/duplicated `colnames`are left asis/made unique; `read10xVisium`: keep barcodes as `colData`; `spatialCoords/<-`: `withDimnames` argument

[HelenaLC]

trafficstars

Addressing #100 ...

• cbind assures unique/duplicated colnamesare left asis/made unique
• in case of duplicates, column names are prefixed with n_... where
  n corresponds to the number of the object being combined
• to retain original barcode identities, these are now kept as colData
  by read10xVisium (previously used as row names and dropped)

... and #103

• added argument withDimnames to spatialCoords getter & setter
• discrepancies b/w colnames(x) and rownames(spatialCoords(x)) throw an error,
  unless withDimnames=FALSE or the latter are NULL

[HelenaLC]

So, can someone accept this if we're okay with the GA (& changes, ofc)?

[drighelli]

the GHA fail during the tests:

── Error ('test_SpatialExperiment-spatialCoords.R:27'): spatialCoords<-,matrix ──
Error in `rownames(xyz) <- NULL`: object 'xyz' not found

do you know why?