Deserialization into POCO

Currently, whenever we have to deserialize the SQL rows from the user's table into a POCO (like [here](https://github.com/Azure/azure-functions-sql-extension/blob/dev/src/SqlBinding/SqlAsyncEnumerable.cs#L117) for the input binding and [here](https://github.com/Azure/azure-functions-sql-extension/blob/dev/src/SqlBinding/TriggerBinding/SqlTableWatcher.cs#L735) for the trigger binding), we first build up a dictionary mapping from column name to column value. We then serialize that dictionary into a JSON string, and then deserialize the dictionary into the POCO type. This is a pretty round-about and inefficient way to do it, so it might be worth looking into alternatives, such as building our own deserializer that uses reflection to map column names to property names.