Make SQLite queries cancellable (#7351)

This change makes SQLite queries (`open foo.db`, `open foo.db | query db
"select ..."`) cancellable using `ctrl+c`. Previously they were not
cancellable, which made it unpleasant to accidentally open a very large
database or run an unexpectedly slow query!

UX-wise there's not too much to show:


![image](https://user-images.githubusercontent.com/26268125/205519205-e1f2ab58-c92d-4b96-9f80-eb123f678ec3.png)

## Notes

I was hoping to make SQLite queries streamable as part of this work, but
I ran into 2 problems:
1. `rusqlite` lifetimes are nightmarishly complex and they make it hard
to create a `ListStream` iterator
2. The functions on Nu's `CustomValue` trait return `Value` not
`PipelineData` and so `CustomValue` implementations can't stream data
AFAICT.

crates/nu-command/src/filesystem/open.rs

@@ -109,7 +109,7 @@ impl Command for Open {
         } else {
             #[cfg(feature = "sqlite")]
             if !raw {
-                let res = SQLiteDatabase::try_from_path(path, arg_span)
+                let res = SQLiteDatabase::try_from_path(path, arg_span, ctrlc.clone())
                     .map(|db| db.into_value(call.head).into_pipeline_data());
 
                 if res.is_ok() {