Refactor create_database_table into Connection.create_table and select_into_database_table, implement Set.

[radeusgd]

Pull Request Description

First part for #6498 - refactoring of the upload infrastructure, in preparation for update_database_table.

Implemented a Set data structure which was long needed.

The APIs are added and an initial implementation is created, but it is not complete - but it has grown significantly already so the remaining implementation will be done as a separate PR.

Adds some basic ability for a function to ensure that it is only executed from within a transaction.

Important Notes

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
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  and
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  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.

[radeusgd]

I added widgets for selecting a column for the primary_key fields in select_into... but they do not seem to show up :/

[radeusgd]

@jdunkerley do you think this could be because the function is an extension function?

Although I'm pretty sure that used to work. Maybe because it is imported with a rename? That would be weird but you never know. Still, ideally I think I'd prefer to figure out this issue as part of the follow-up PR (unless I did some obvious mistake that I'm missing here).

[jdunkerley]

Looks good to me.

[radeusgd]

The widgets are behaving weirdly

Enso_KsdavNafWb.mp4

I set up a custom @primary_key Widget_Helpers.make_column_name_vector_selector annotation but it seems to be not picked up.

I see both a dropdown for Nothing as well as a Vector Editor plus (I think only one of these 2 should show up for a single parameter, no? in this case vector editor should probably take over, especially as its requested by the widget)

Moreover, when I add an element with Vector Editor - Nothing gets added, even though the Vector is of Text, not Nothing and it has the column selection widget which somehow does not get picked up.

cc: @Frizi