Initial commit: boarding pass to AirTrail pipeline

Photograph/screenshot a boarding pass, decode its BCBP barcode (PDF417/
Aztec/QR/DataMatrix), fetch the historical flight track from FlightAware
the day after the flight, stage it for review, and write it into AirTrail
via its REST API on approval. ntfy notifications carry signed
Approve/Deny/Investigate actions.

.env.example

@@ -0,0 +1,16 @@
+# Public URL this service is reached at through NPMplus/Authelia. Required
+# for ntfy notification links and the Approve/Deny callback URLs to work.
+PUBLIC_BASE_URL=https://boarding-pass.example.com
+
+# AirTrail instance and API key (create the key in AirTrail's account UI).
+AIRTRAIL_BASE_URL=https://airtrail.example.com
+AIRTRAIL_API_KEY=
+
+# Container timezone. Set explicitly - flight_date + 1 day and the daily
+# job's run time are date-sensitive.
+TZ=Australia/Sydney
+
+# Max boarding pass photo upload size, in MB.
+MAX_UPLOAD_MB=15
+
+PORT=8080