Check out: DB side default values

[PDT42]

If we mark a value as "required=False", up until now our database connection fills the values spot in the query with 'null' - which means we provide a value for the column. If instead, we were to enable AnyBase to create default values on a database level We'd need to:

• Add default value statements in the create_table function.
• Add default value to the columns string representation as stored in asset type
• Definitely create tests for all of this 😅
• Any other place?