Lazy reaping (#4895)

* Squash and rebase from gav-lazy-reaping

* Bump version

* Bump runtime again

* Docs.

* Remove old functions

* Update frame/balances/src/lib.rs

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

* Update frame/contracts/src/lib.rs

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

* Warnings

* Bump runtime version

* Update frame/democracy/src/lib.rs

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

* Update frame/system/src/lib.rs

* Clean up OnReapAccount

* Use frame_support debug

* Bump spec

* Renames and fix

* Fix

* Fix rename

* Fix

* Increase time for test

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Benjamin Kampmann <ben.kampmann@googlemail.com>

substrate/bin/node-template/runtime/src/lib.rs

@@ -164,7 +164,7 @@ impl system::Trait for Runtime {
 	/// What to do if a new account is created.
 	type OnNewAccount = ();
 	/// What to do if an account is fully reaped from the system.
-	type OnReapAccount = Balances;
+	type OnKilledAccount = ();
 	/// The data to be stored in an account.
 	type AccountData = balances::AccountData<Balance>;
 }