Parallel clusters don't respect environment manipulations (in particular libpaths)

[gowerc]

When creating parallel clusters the users current environment is not taken into consideration. I.e. if the user manually changed their lib paths this would not be reflected in the parallel process.

This is kind of an anti-pattern as if the users are configuring their libpaths this should be done globally via the .Rprofile file so question (1) would be do we want to provide a solution for this?

If yes; 1 option could be that the ncores argument could take a cluster object which gives the user an entrypoint to manually configure the path (or other oddities of their project) prior to handing us the cluster.

Another option could be we just extend a "lib" argument for setting lib paths in the clusters (assuming that is the only oddity that they might want to configure).