Enhanced error handling and user guidance

[HRemonen]

It's best practice to allow the user to make mistakes and provide guidance on how to fill in the form. The form now introduces user guiding errors, which is good, however I would like to introduce a more refined type of form validation method:

https://hds.hel.fi/patterns/forms/form-validation/#validation-summary-pattern

• [x] Create ErrorSummary component
• [x] Add Zod schema validation for the form on client side
• [x] Associate the validation issues with fields with id attributes
• [x] Add Inputfield error values and helper texts
• [x] Create translations for the error messages and such
• [x] Remove old error stuff -> also remove from tests, remember to also remove DeleteIcon mocs etc.
• [x] Add new tests -> Probably also own tests for the ErrorSummary component