Building all wasm crates in one workspace was a nice idea, however it
just introduced problems:

1. We needed to prune old members, but this didn't worked for old git
deps.
2. We locked the whole wasm workspace while building one crate. This
could lead to infinitely locking the workspace on a crash.

Now we just build every crate in its own project, this means we will
build the dependencies multiple times. While building the dependencies
multiple times, we still decrease the build time by around 30 seconds
for Polkadot and Substrate because of the new parallelism ;)

This removes the requirement on wasm-builder-runner by using the new
`build_dep` feature of cargo. We use nightly anyway and that enables us
to use this feature. This solves the problem of not mixing
build/proc-macro deps with normal deps. By doing this we get rid off
this complicated project structure and can depend directly on
`wasm-builder`. This also removes all the code from wasm-builder-runner
and mentions that it is deprecated.

Modified-by: Bastian Köcher <git@kchr.de>

…improvements

…improvements

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>