add get_interchain: trace a transaction/block to validator blocks + interchain anchors

New transaction.get_interchain and block.get_interchain call the prime-node
/api/v1/{transaction,block}/{id}/interchain endpoints, returning an
InterchainTrace {block_id, validator_blocks, interchain_transactions}. Adds
VerificationBlock / InterchainTransaction / InterchainTrace dataclasses with
from_dict, exports them, and a from_dict test.

prime_sdk/__init__.py

@@ -48,6 +48,8 @@ from .models import (
     BlockHeader,
     BlockProof,
     GrpcConnectionInfo,
+    InterchainTrace,
+    InterchainTransaction,
     ListResponse,
     ListTransactionsResponse,
     SmartContract,
@@ -67,6 +69,7 @@ from .models import (
     TransactionType,
     TransactionTypeCreateRequest,
     TransactionTypeCreateResponse,
+    VerificationBlock,
 )
 from .system import SystemClient
 from .transaction import TransactionClient
@@ -125,6 +128,8 @@ __all__ = [
     "BlockHeader",
     "BlockProof",
     "GrpcConnectionInfo",
+    "InterchainTrace",
+    "InterchainTransaction",
     "ListResponse",
     "ListTransactionsResponse",
     "SmartContract",
@@ -144,4 +149,5 @@ __all__ = [
     "TransactionType",
     "TransactionTypeCreateRequest",
     "TransactionTypeCreateResponse",
+    "VerificationBlock",
 ]