Transform list of unicode chars in templater

Since OTP 17 strings read from a file are by default parsed as a list of
unicode characters.
If such a list contains a non-ascii character (unicode > 255) then a
call to erlang:list_to_binary/1 fails.
This commit converts unicode list of chars to binary via unicode module
if ran against OTP >= 17.
Can this work as `[34,122,97,380,243,322,263,32,103,281,347,108,261,32,106,97,378,324,34]`?