In a load balancing scenario, the UserSession from more than one server
may end up storing the session same session cookie. This is particularly
true when one rserver routes the request to another for load balancing...
in that case, both rservers will get the same auth cookie to represent
that session.

Now that we invalidate all auth cookies when a user signs out, on all
servers in the cluster, that means some of them will try to insert a
record into the DB that's already there. We just need to ignore those
specific errors.

This is now done in invalidateUserSession for all cookies.

For postgres, the extra call causes an error in the logs on signout.

- before this change, the current cookie was not in the
UserSession, which meant that if two tabs were directly addressing
different servers in the cluster, using different server:port
(and thus different cookie domains), the most recent cookie in one cluster
would not get revoked if the other session was signed out.

It's safer to make sure all cookies used by a UserSession for one member in the
cluster get revoked when another server revokes a cookie (i.e. the user signs out from there)

original PR:

   rstudio/rstudio-pro#3381

…sion communication (#10885)

* reduce risk of port collision when launching desktop

* tweaks

* add some debug logging

* tweaks

* naming

* add extra debugging

* avoid rand() when generating shared secret

* avoid macro collision

* avoid logging shared secret in package builds

* PR feedback

* remove unused headers

* a couple more tweaks

companion to: rstudio/rstudio-pro#3341

* revert use of UTF-8 code page on Windows

* bump patch version

Corrected the issue number for one of the feature updates.

* update delegating functions for v15: defineGroup, useGroup, releaseGroup, stroke, fill, fillStroke, capabilities
* set default version to 15
* update rCompatibleGraphicsEngineVersion_ in the headers file

Generate Mac OS packages with a `-` instead of a `+`

This reverts commit 1d79453.