ui: add option in builder to provide a string template for array item names

[miguelgrc]

Right now, there's the option to provide (manually editing the schema) a pattern to set the titles of the array items based on the selected content of each item (see stringify and stringifyTmpl in the schemas). It would be nice to have an option in the form builder for users to specify this pattern (optionally with some help, i.e. when they input {{ they get path suggestions, getting inspiration from the SchemaPathSuggester).

Extra considerations:

• This should actually go in the form builder library once it's released
• It now uses Squirrelly, which at the moment is not compatible with ESModules, needing the following extra config in vite.config.js:

  build: {
    commonjsOptions: {
      transformMixedEsModules: true,
    },
  },

  We can review this and see if by the time we tackle this task there is a new version that supports ESModules or if there's an easy, maybe smaller alternative to use. Otherwise it's not a big problem leaving it as it is. Forget it, version 9 is already out and seems to work with ESModules out of the box

[miguelgrc]

Moved to formule: https://github.com/cern-sis/react-formule/issues/24