Add internal models

These internal models are introduced to reduce decoupling. The idea is to operate internal model within the project boundaries and convert to appropriate Connect or SDK models in the places where it's necessary.

pkg/onepassword/model/vault_test.go

@@ -0,0 +1,36 @@
+package model
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	connect "github.com/1Password/connect-sdk-go/onepassword"
+	sdk "github.com/1password/onepassword-sdk-go"
+)
+
+func TestVault_FromConnectVault(t *testing.T) {
+	connectVault := &connect.Vault{
+		ID:        "test-id",
+		CreatedAt: time.Now(),
+	}
+
+	vault := &Vault{}
+	vault.FromConnectVault(connectVault)
+
+	require.Equal(t, connectVault.ID, vault.ID)
+	require.Equal(t, connectVault.CreatedAt, vault.CreatedAt)
+}
+
+// TODO: check CreatedAt when available
+func TestVault_FromSDKVault(t *testing.T) {
+	sdkVault := &sdk.VaultOverview{
+		ID: "test-id",
+	}
+
+	vault := &Vault{}
+	vault.FromSDKVault(sdkVault)
+
+	require.Equal(t, sdkVault.ID, vault.ID)
+}