Change behavior of left and right keys to scroll faster horizontally

[nrm21]

Sometimes one wants to show a pods log in k9s without word wrap (possibly it messes with the formatting). k9s already allows for left-right movement to show the remainder of log lines however it goes one character at a time and is painfully slow for long lines. This minor change moves 30 chars at a time and makes the log behave more like 'less -S' does with long lines.

Behavior of 'h' and 'l' keys remains unchanged.