Build WASM binaries as part of cargo build (#2868)

* Introduce `wasm-builder` and `wasm-builder-runner` to retire `build.sh`

Make use of `wasm-builder` in `test-runtime`.

* Add build script and remove the wasm project

* Port `node-runtime` to new wasm-builder

* Make `substrate-executor` tests work with `wasm-builder`

* Move `node-template` to `wasm-builder`

* Remove `build.sh` :)

* Remove the last include_bytes

* Adds the missing build.rs files

* Remove `build.sh` from CI

* Debug CI

* Make it work in CI

* CI attempt 3

* Make `substrate-runtime-test` compile on stable

* Ahhh, some missed `include_bytes!`

* AHH

* Add suggestions

* Improve search for `Cargo.lock` and don't panic if it is not found

* Searching from manifest path was no good idea

* Make the `wasm-builder` source better configurable

* Expose the bloaty wasm binary as well

* Make sure to rerun WASM recompilation on changes in dependencies

* Introduce new `WASM_BUILD_TYPE` env and make sure to call `build.rs` on
changes to env variables

* Remove `build.sh` from READMEs

* Rename the projects

* Fixes CI

* Update lock file

* Fixes merge-conflict

* Apply suggestions from code review

Co-Authored-By: TriplEight <denis.pisarev@parity.io>

* Try to make windows happy

* Replace all back slashes in paths with slashes

* Apply suggestions from code review

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Use cargo from `CARGO` env variable

* Fix compilation

* Use `rustup` for running the nightly build

* Make individual projects skipable

* Fix compilation

* Fixes compilation

* Build all WASM projects in one workspace

* Replace more back slashes!

* Remove `inlcude_bytes!`

* Adds some documentation

* Apply suggestions from code review

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Apply suggestions from code review

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* More review comments

* Update `Cargo.lock`

* Set license

* Apply suggestions from code review

Co-Authored-By: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

* More review comments + adds `TRIGGER_WASM_BUILD` env

* Fix doc tests

* Increase version + update README

* Switch crates.io version of `wasm-builder`

* Update README

* Switch to released version of `wasm-builder-runner`

substrate/README.adoc

@@ -264,7 +264,6 @@ Then build the code:
 
 [source, shell]
 ----
-./scripts/build.sh          # Builds the WebAssembly binaries
 cargo build                 # Builds all native code
 ----
 
@@ -309,6 +308,24 @@ cargo run --release \-- \
 
 Additional Substrate CLI usage options are available and may be shown by running `cargo run \-- --help`.
 
+== WASM binaries
+
+The WASM binaries are built during the normal `cargo build` process. To control the WASM binary building,
+we support multiple environment variables:
+
+* `SKIP_WASM_BUILD` - Skips building any WASM binary. This is useful when only native should be recompiled.
+* `BUILD_DUMMY_WASM_BINARY` - Builds dummy WASM binaries. These dummy binaries are empty and useful
+                              for `cargo check` runs.
+* `WASM_BUILD_TYPE` - Sets the build type for building WASM binaries. Supported values are `release` or `debug`.
+                      By default the build type is equal to the build type used by the main build.
+* `TRIGGER_WASM_BUILD` - Can be set to trigger a WASM build. On subsequent calls the value of the variable
+                         needs to change. As WASM builder instructs `cargo` to watch for file changes
+                         this environment variable should only be required in certain circumstances.
+
+Each project can be skipped individually by using the environment variable `SKIP_PROJECT_NAME_WASM_BUILD`.
+Where `PROJECT_NAME` needs to be replaced by the name of the cargo project, e.g. `node-runtime` will
+be `NODE_RUNTIME`.
+
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