fix local setup, readOnly fields and cypress tests

[miguelgrc]

• The local setup (simple way) was not working without yarn linking react and react-dom. Now, by adding a dedupe statement for those two dependencies, it works out of the box without the need to use yarn link. Note that for the advanced way (i.e. linking the bundle) yarn link is still needed as mentioned in formule-demo's readme. Some legacy yarn commands have been removed as well.
• Cypress tests were failing:
  • readOnly fields were not working anymore after a bug was introduced in rjsf v5.18.x (Regression: readOnly not working in 5.18.5 rjsf-team/react-jsonschema-form#4236), it has been solved in v5.19.0 so the version has been bumped.
  • Selectors were failing since we had changed the rjsf separator from the default _ to $. I have found ! to be more convenient and easier to adapt the tests to work again with so I have changed it. I have also updated the tests accordingly and overwritten the get and find cypress methods to escape the ! character so that we don't have to do it manually (\\!) every time.
  • Cypress has been bumped to the latest version, which has also corrected an issue that made us unable to use moduleResolution: bundler in formule-demo (Unable to compile TypeScript with "moduleResolution": "bundler" option in v5 cypress-io/cypress#27731). Some compiler settings have been updated accordingly.

Also closes #61