Welcome to the forum!
Yes, a front drum brake bike can be converted to a front disc brake. You would need the following from a 2001 and up model year bike, minimum:
-Front wheel hub with brake disc and front axle
-Front brake caliper, brake line, brake lever/handlebar perch with master cylinder
-Lower left fork leg
The easiest way to perform this mod would be to find an entire front end from a 2001 and up model year bike.