Add support for dynamic number of fields in certificate generation

[yogendrasai02]

• Right now, the certificate generation tool deals with 'Name' and 'Date' only.
• To make it more flexible, we would ideally need to give the number of fields, as well as deal with those fields.
• For example, I might want to have 3 fields for Name, College, Rank in one event's certificate. For another usecase, I might want to have 4 fields.
• The updated tool must do this task. Fields are dynamic and based on the number of fields, while marking position using OpenCV on the certificate template, those number of fields must be handled.