Add head 2 head stats to daily schedule

[Peter Monks]

When the daily schedule is sent out, I want to see the two teams' head-to-head stats, so I can get a sense of how they've fared vs each other in the season to date.

Potential Solutions:

Within the PDF generation code, call the football-data "match" endpoint in order to obtain the head2head data (which is not included in the "list of matches" endpoint's response) for that match, then include that data in the generated PDF.

Note that this will case an "N+1 SELECTs" problem, which may be an issue especially on days with large schedules (the free tier can only make 10 API calls per minute). There is code present that detects and sleep/retries when the quota is exceeded however.