Remove .wasm from all distributions, and .so from source distributions
.so is still built, but only for binary distributions (it can be built from a source distribution).
To do this, we now include intermediary files (parser.c in particular) in the source distribution. They are not really source file, but this allows removing the dependency on a nodejs runtime to install from pypi.
Migrated from D6131 (view on Phabricator)