[RFC] UMA: Universal Modular Accelerator Interface

Thanks everyone for the detailed input and feedback!

To keep track of the latest version of the UMA pre-RFC and to add the great suggestions that we got from this discussion thread, I created a document in our tvm-rfc fork :

CC: @areusch @mbs-octoml @jroesch @cgerum @paulpb @PhilippvK @r.stahl @aca88 @SebastianBoblestETAS @manupa-arm