RPC submitpackage: change return format to allow partial errors

Behavior prior to this commit allows some transactions to
enter into the local mempool but not be reported to the user
when encountering a PackageValidationResult::PCKG_TX result.

This is further compounded with the fact that any transactions
submitted to the mempool during this call would also not be
relayed to peers, resulting in unexpected behavior.

Fix this by, if encountering a package error, reporting all
wtxids, along with a new error field, and broadcasting every
transaction that was found in the mempool after submission.

Note that this also changes fees and vsize to optional,
which should also remove an issue with other-wtxid cases.

test/functional/mempool_sigoplimit.py

@@ -34,7 +34,6 @@ from test_framework.util import (
     assert_equal,
     assert_greater_than,
     assert_greater_than_or_equal,
-    assert_raises_rpc_error,
 )
 from test_framework.wallet import MiniWallet
 from test_framework.wallet_util import generate_keypair
@@ -169,7 +168,8 @@ class BytesPerSigOpTest(BitcoinTestFramework):
         assert_equal([x["package-error"] for x in packet_test], ["package-mempool-limits", "package-mempool-limits"])
 
         # When we actually try to submit, the parent makes it into the mempool, but the child would exceed ancestor vsize limits
-        assert_raises_rpc_error(-26, "too-long-mempool-chain", self.nodes[0].submitpackage, [tx_parent.serialize().hex(), tx_child.serialize().hex()])
+        res = self.nodes[0].submitpackage([tx_parent.serialize().hex(), tx_child.serialize().hex()])
+        assert "too-long-mempool-chain" in res["tx-results"][tx_child.getwtxid()]["error"]
         assert tx_parent.rehash() in self.nodes[0].getrawmempool()
 
         # Transactions are tiny in weight