Request: better default R_LIBS_USER

Hi,

I see R by default installs packages in ~/R. I know I can change the
default directory with R_LIBS_USER, but software shouldn't be
polluting the home directory.

For example both python and node install packages to ~/.local/lib,
ruby to ~/.local/share. They don't install to for example ~/node.

R should do the same: it should install packages to somewhere inside
~/.local by default.

Cheers.

Felipe Contreras