Refactor handling nested form fields from custom BEM-alike structure to Formik nesting approach #37
Description
Current approach of handling nested form fields (used rather only for technicalSpecs related fields) in components such as NewProduct and ModifyProduct is difficult to maintain and extend due to the need of mapping the structure from BEM-alike: technicalSpecs__long_field_name__nested_field_name to a proper object-alike one and the other way back to BEM-alike again.
Formik has a built-in way of handling nested form structures: https://formik.org/docs/guides/arrays, which should solve problems related to current structure and simplify code (as well as shortening it).