Hex to text converter feature

[roman-yagodin]

Use case - copy string representation of T-SQL varbinary (e.g. 0x3C3F786D6C...) and convert to text in different encodings (UTF-8, Windows-1251, Windows-1252, etc.) Would be useful in cases then varbinary contains plain text, XML, JSON, etc.

Add support for optional "0x" prefix.