Allow using GPU update with DD and update groups

Allow using GPU update with DD and update groups

The GPU update is now can be enabled for the supported DD cases
with the GMX_FORCE_UPDATE_DEFAULT_GPU environment variable. Also
added the checks on whether the SHAKE algorithm was requested,
since SHAKE is not supported by the GPU update.

Refs. #3226, #3163.

Change-Id: I57e3ad3b8a571ec244989e888afd5cfcbaf9b75e