Add support for dynamic number of fields in certificate generation

- 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.

Start by locating the certificate generation entry point and the code that currently handles the Name and Date fields. Trace how OpenCV marks positions on the certificate template, then define how a supplied field count and field values should be represented. Done means the tool supports certificates with varying numbers of fields, including the three- and four-field examples.

Written by the indexing model from the issue text.