Add Mutation Support for StorageMemory

Why it matters

Before this feature, the Memory storage engine did not support mutations, which limited the ability to perform UPDATE or DELETE operations on in-memory tables. This enhancement allows users to perform mutations on Memory tables, enabling more flexible and dynamic in-memory data manipulations.

How to use it

Users can now perform mutation queries such as ALTER TABLE memory_table DELETE WHERE condition or ALTER TABLE memory_table UPDATE column = value WHERE condition on tables created with the Memory engine, just like with other mutable table engines.