Cli: move airdrop to rpc requests (#16557)

* Add recent_blockhash to requestAirdrop

* Move tx confirmation to separate method

* Add RpcClient airdrop methods

* Request cli airdrop via RpcClient

* Pass optional faucet_addr into TestValidator and fix tests

* Update client/src/rpc_client.rs

Co-authored-by: Michael Vines <mvines@gmail.com>

Co-authored-by: Michael Vines <mvines@gmail.com>

core/tests/client.rs

@@ -34,7 +34,7 @@ fn test_rpc_client() {
     solana_logger::setup();
 
     let alice = Keypair::new();
-    let test_validator = TestValidator::with_no_fees(alice.pubkey());
+    let test_validator = TestValidator::with_no_fees(alice.pubkey(), None);
 
     let bob_pubkey = solana_sdk::pubkey::new_rand();