[Feature Request] Implement experimental mesh nodes

[pow2clk]

Is your feature request related to a problem? Please describe. Work graphs are limited to compute shaders at present. There is discussion in the work graphs spec itself about adding graphics leaf nodes to give the calculations performed by work graphs a path to the screen. The mesh node approach is formally proposed here

Describe the solution you'd like Support for mesh nodes could be done by replacing the input payload of a mesh shader with a node input record for a mesh node. Such nodes would be denoted using a new lauch type: [NodeLaunch("mesh")].

Describe alternatives you've considered While more complete support for graphics leaf nodes would be useful, mesh shader interfaces present a relatively simple modification that allows feeding work graphs output into the graphics pipeline without too many interface changes.