feat: support memtx map tuple size configuration

Summary

• feat: support memtx map tuple size configuration

---

• Close #1200 (closed)
• Cherry-pick to: none
• Docs follow-up: not necessary / new issue
• Changelog is updated

test/int/test_config_file.py

@@ -108,6 +108,7 @@ instance:
             memtx=dict(
                 memory=dict(value="64M", source="default"),
                 checkpoint_count=dict(value=2, source="default"),
+                max_tuple_size=dict(value="1M", source="default"),
                 checkpoint_interval=dict(value=3600.0, source="default"),
             ),
             vinyl=dict(