Upgrade to v5 schema

Now uses:
* ipld direct_by_leaf StateDB for basic queries
* trie_by_cid StateDB for trie slice and proof queries

Also:
* vulcanize => cerc refactor
* Backend method to close dbs
* state tests are in multiple packages, to allow separate ginkgo suites
* removes gap-filler module
* integration tests and github workflows
* run stack-orchestrator for testnet
* fix various issues with tests, hardhat server, dockerfile
* fix cmd flags / env vars
* fix flaky tests and clean up code
* remove unused code, scripts
* remove outdated docs
* update version

test/contract/contracts/GLDToken.sol

@@ -1,5 +1,6 @@
 pragma solidity ^0.8.0;
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
 contract GLDToken is ERC20 {
     constructor() ERC20("Gold", "GLD") {
         _mint(msg.sender, 1000000000000000000000);