[Feature Request]: Allow users to define default data types

### What would you like to happen?

The "Insert / Update" transform automatically generates SQL code to create a target table in case it does not exist.
For strings, it uses the data type "varchar" as default.
In my case, I always use "nvarchar". Currently, the only way to achieve this is by performing a text replacement in an external editor.

I think it would be great if there were a setting that would allow users to define the default type.

Maybe a simple solution could be a mapping table like this

DefaultType ReplaceWith
varchar nvarchar

The fields should probably be pulldowns that simply list all available data types, i.e. all those that are being used by Hop.
I know this could lead to nonsensical selections (like replace varchar with boolean), but I would argue that this is the user's respsonsibility.

This is [in relation to this conversation on Mattermost.](https://chat.project-hop.org/hop/pl/q7nd6pf9yfgcdpypbc3ypbwowc)

### Issue Priority

Priority: 3

### Issue Component

Component: Hop Gui

Start with the Hop Gui implementation of the Insert / Update transform and trace where it generates SQL for a missing target table. Check how transform settings are represented and how available data types are exposed. Done means users can configure a default-type mapping such as varchar to nvarchar and generated table SQL applies it.

Written by the indexing model from the issue text.