ability to insert row

[cldellow]

• [x] ~Add /db/table/-/dux-insert~ Handle /db/table/dux-insert specially
• [x] It will render the insert-row template with an extra body class of insert-row.
• [x] You must have the insert-row permission.
• [x] Link to it on the database page.
• [x] _dux_edit=1 should be assumed for the insert page, even if the table is not default-editable
• [x] We shouldn't show a delete-row option.
• [x] Save button should use the insert API endpoint
• [x] Be able to redirect you to the correct page
  • I'm willing to cheat here and only support single column pkey if it makes our life easier
• [x] Have a default value for not null date/times -- the UI makes it seem as though there is a value set, when there really isn't

The response from the insert endpoint looks like:

{"ok": true, "rows": [{"id": null, "user_id": 5428, "name": "Autobiographer", "date": "2023-02-16 22:17:00.000"}]}

...so we'll have to know what the pkey columns are. Maybe we can dump those into a JS variable on the page.

[cldellow]

Hmm. I tried adding a new route at /db/table/-/dux-insert. It seems kinda fiddly - if I want to re-use the row template, I need to make sure I have the right context object.

Then I'll still need to invoke the render_cell / edit_control hooks myself.

I think I might try this from a different, more disgusting angle: respond on /db/table/dux-insert.

We'll monkey patch Datasette.resolve_row to return a candidate row.