Format and Sort features in Cargo.toml files (#14803)

* CI: Add feature sorting check

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Sort all features

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add some mistakes

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Revert "Add some mistakes"

This reverts commit b2b1099f979f6decb22d09b46689c1554bb72e81.

* CI job naming

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add oneliner formatting

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Explain tool

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Use latest version

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Better erorr message

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Format after master merge

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Use --check option

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Messed up the merge commit...

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/scripts/ci/gitlab/pipeline/test.yml

@@ -58,6 +58,17 @@ cargo-fmt:
     - cargo +nightly fmt --all -- --check
     - rusty-cachier cache upload
 
+cargo-fmt-manifest:
+  stage: test
+  extends:
+    - .docker-env
+    - .test-refs
+  script:
+    - cargo install zepter --locked --version 0.10.0 -q -f --no-default-features && zepter --version
+    - echo "👉 Hello developer! If you see this CI check failing then it means that one of the your changes in a Cargo.toml file introduced ill-formatted or unsorted features. Please take a look at 'docs/STYLE_GUIDE.md#manifest-formatting' to find out more."
+    - zepter format features --check
+  allow_failure: true # Experimental
+
 cargo-clippy:
   stage: test
   # this is an artificial job dependency, for pipeline optimization using GitLab's DAGs