Change license of node-template and FRAME examples to MIT-0 (#13465)

* Change node-template license from Unlicense to MIT-0

* Change frame examples license from Unlicense to MIT-0

* Update bin/node-template/LICENSE

---------

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: parity-processbot <>

substrate/frame/examples/offchain-worker/README.md

@@ -26,4 +26,4 @@ Additional logic in OCW is put in place to prevent spamming the network with bot
 and unsigned transactions, and custom `UnsignedValidator` makes sure that there is only
 one unsigned transaction floating in the network.
 
-License: Unlicense
+License: MIT-0