Add server-side table sorting

[lovasoa]

Closes #1442

Summary

• add opt-in server_sort_column table headers that reload with sort_<column>=ASCENDING|DESCENDING
• preserve existing in-browser sort behavior for other columns
• document the property and use it in the simple website example

Testing

• npm test
• npx playwright test fixtures/table-server-sort/test.ts --project=fixtures --reporter=line
• hurl --test --error-format long examples/simple-website-example/test.hurl

[cbertelli]

I don't think that it is necessary to limit sorting to the indexed columns. The user may decide to wait. It would be very useful to point out the absence of an index, but sorting should be effective and allowed anyway.
The problem may arise when a column is decoded by an alphanumeric label. The user will not expect the column to be sorted by the integer id or even an alphanumeric code, he will expect it to be sorted by label. This is indexed, sure, but references another table and the interface is asked to show a sorted label, not a sorted code/id (I hope it's not too obscure).