Remove unused key types sr25 and ed25 (#3659)

* Remove unused key types sr25 and ed25.

* Restore in specific files to fix build.

* Fix runtime tests

* Fix keystore test

* Revert typo

* Move keytypes to primitives/src/testing.rs

* More missed items.

* Getting close now.

* Fix example in documentation.

* Update core/application-crypto/src/ed25519.rs

* Update core/application-crypto/src/sr25519.rs

* Bump impl version.

substrate/node/runtime/src/lib.rs

@@ -85,7 +85,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
 	spec_version: 160,
-	impl_version: 160,
+	impl_version: 161,
 	apis: RUNTIME_API_VERSIONS,
 };