Describe the problem to be solved

Forms are great but redirecting to a submission related page would be great.

So far, a trick is possible (based on the latest submission) but it is not guaranteed (in case of concurrent submissions) to show the relevant data.

We have a document with input columns and output columns computed with formulas.
We relied on a card view but is a very constrained in term of UI.

This PR allows to redirect to a fully custom UI or to a grist page with a specific anchor such as
http://localhost:8484/o/docs/bS42RAoQBs1W/test#a1.s5.r##.c2

Describe the solution you would like

Allow id substitution in the redirection URL with ## (but that's a proposal).

This is a working branch here https://github.com/betagouv/grist-core/tree/add-id-substitution-in-form-redirect-url