Break appcrypto dep cycle (#4347)

* move application-crypto tests into seperate crate

* Fix crate name, update script and add docs

* pressing 'save' helps

* remove useless lines

* adding header

* split into actual modules

substrate/docs/Upgrade.md

@@ -0,0 +1,5 @@
+# Upgrade path for you building on substrate
+
+## master
+ - crate rename has been fixed `sp-application-crypto` (was `sc-application-crypto`);  `.maintain/rename-crates-for-2.0.sh` has been updated accordingly, you can use it to upgrade to latest naming convention
+ - crates have been renamed, run `bash .maintain/rename-crates-for-2.0.sh`