[Task] SQL in Browser #597

We can use sql.js to evaluate SQL in browser and on the server. This should help with providing both client and server evaluation of a task.

The task needs a few settings:

• instruction: string
• defaultQuery: string

For evaluation, it should check whether the resulting datasets are equal. We can use EXCEPT to check that.

• db: URL to a sqlite3 database
• query: Solution query to compare against

For feedback, there should be a few checks:

• Report mismatched row count: If EXCEPT returns rows
• Report mismatched column count: If EXCEPT errors with "SELECTs to the left and right of EXCEPT do not have the same number of result columns"
• Report mismatched/unordered columns: If EXCEPT returns all rows
• Show query result as table

For the UI, we only need a code input with highlighting for the SQL query.