Cleanup util-crypto & keyring imports (#314)

* Cleanup util-crypto & keyring imports

* Adjust util imports for types

* Bump deps

docs/examples/promise/07_transfer_dots/index.js

@@ -1,6 +1,6 @@
 // Import the API, Keyring and some utility functions
 const { ApiPromise } = require('@polkadot/api');
-const Keyring = require('@polkadot/keyring').default;
+const { Keyring } = require('@polkadot/keyring');
 const u8aFromUtf8 = require('@polkadot/util/u8a/fromUtf8').default;
 
 const ALICE_SEED = 'Alice'.padEnd(32, ' ');