Feat: bundle functionality

packages/model/metabundle/metabundle.go

+package metabundle
+
+import (
+	"github.com/iotaledger/goshimmer/packages/model/meta_transaction"
+	"github.com/iotaledger/goshimmer/packages/ternary"
+)
+
+type MetaBundle struct {
+	hash              ternary.Trytes
+	transactionHashes []ternary.Trytes
+}
+
+func New(transactions []*meta_transaction.MetaTransaction) (result *MetaBundle) {
+	result = &MetaBundle{
+		hash: CalculateBundleHash(transactions),
+	}
+
+	return
+}
+
+func (bundle *MetaBundle) GetTransactionHashes() []ternary.Trytes {
+
+}
+
+func (bundle *MetaBundle) GetHash() {
+
+}
+
+func CalculateBundleHash(transactions []*meta_transaction.MetaTransaction) ternary.Trytes {
+	return ternary.Trytes("A")
+}