[Rd] Feature request: Change default library path on Windows

[Steve Haroz]

> So I would say that I still believe Microsoft doesn't give clear
> guidance for this.

Sure, there is some ambiguity on where MS would prefer these kinds of
files. But what is clear is that the current location USER/Documents
is causing a serious issue.

And while we can all understand frustration with Microsoft, Windows
users represent a major proportion of the R install base. So let's see
what we can do to help out those users. Changing the default location
to either USER/R or USER/AppData/Local/R would help a lot of users,
both beginners and those with moderate experience who switch to a new
cloud backup.

Microsoft is unlikely to put out new guidance any time soon. And the
current guidance doesn't seem opposed to putting R libraries in either
suggested location. So how about we just pick one (I suggest USER/R
for simplicity) and discuss how to go about making the change?

-Steve