Change commandText property/parameter name

Currently input and output bindings share an attribute - and with that share the [commandText](https://github.com/Azure/azure-functions-sql-extension/blob/main/src/SqlAttribute.cs#L44) property/parameter

This value can be multiple things based on the type of binding :

Input - Either a query or the name of a stored procedure
Output - The table name to upsert to

So out of the 3 potential options only one is really a "commandText".

To make it much more clear we should consider the following :

- Renaming it to `queryOrStoredProcedure` and using that for input bindings
- Adding a new property/parameter `tableName` and using that for output bindings (similar to the trigger attribute)

This is a pretty big breaking change, but would help make things a lot more clear when using the bindings.