Validate domain names before auction

[vohmar]

We have at least one instance of auction for a domain name that cannot exist: hhla_tk.ee (underscore is not allowed in domain names)

to prevent auctions for a domains that cannot be registered we should add a validation check to make sure the domain name is valid according to .ee domain regulations:

• The Domain Name may only contain numbers (0-9), dashes and letters.
• name may not begin or end with a dash;
• name may not contain a dash simultaneously as the third or fourth symbol.
• The minimum length of a name is 1 symbol and the maximum length is 63 symbols.
• Marks of identification, the symbols of which do not correspond to ASCII, are not registered as a Domain Name, with the exception of the letters of the Estonian alphabet.