Vendor-agnostic device information

[efaulhaber]

It would be nice if we could do something like KernelAbstractions.devices(backend) or so to print the name of the device we're working on.
And even further: a KernelAbstractions.versioninfo(backend) to print the CUDA version and so on. This could be very useful for logging.

[vchuravy]

Might also make sense to add versioninfo(backend).

[pxl-th]

Maybe even an interface to query common device properties. Currently I have to define extensions to query for amount of shared memory available on the device:
https://github.com/pxl-th/NNop.jl/tree/master/ext