document existance of wasm artifacts

[trinity-1686a]

Following Plume-org/Plume#570 and Plume-org/Plume#571, we can now provide wasm binaries for non tier 1 platforms.
This should be documented (and those binaries distribued) so that people wanting to build Plume on "rare" platforms can do so without the headache of doing whatever was done to make arm build fine