create sign up(anketa) page

[ihor-bobyr]

create https://programming.org.ua/en/anketa (first step)

• render all inputs
• add simple validation
• validate age of user and navigate correctly
  • >= 17 yo -> anketa/adults
  • >=12 && < 17 yo -> anketa/teens
  • < 12 yo -> show warning and stay on the page

[k-boiko]

I think we will just create different pages for each step so I will update the description of this issue to be only about first step of sign up

[ihor-bobyr]

reset isVisited local storage flag for #53