feat: deploy pgbackup (#227)

`pgbackup` is going to take over the backup process that currently runs
on the database instance itself, since that doesn't seem to be very
reliable at the moment. This has some small benefits over the existing
approach:

* Logs are automatically shipped to S3 by `vector`
* Rust is more maintainable than Bash
* We can do more complicated logic in the future

This change:
* Adds the definition for `pgbackup`

f2/config.yaml

@@ -91,3 +91,17 @@ services:
       RUST_LOG: trace
       COOKIE_KEY: secret:q9AGDzX5Iv4PvJTBJy1UJQUpLgdF6WU19tYyfFPYwuJ7078zz2e/0Ozz1QE7UHRQv0pOeoZItewnMl13HWQ8dWAfZEHrRztup19N7g2fO3MuIZrznmkrWtlroHai6865G3N/yCI+HS32PGhE+zLdxfG/6saQJG4cR2943e7BI/von0e+sgJ1QejZ8eIXbXOH3i0fUi/kg5GvDJCbqQnoLEd+XIAdWdMQNNp8VR65OxfiFlH3Z+fFmHNiNDys2tGG1nYCnEtXCdVLCCy4lO/iDNzlJxfVG2cAe0vA0xtm3JcfewAR/n40BranWnI7TKQ/u7URihxnNA4/7Hzbq331FQ==
       JWT_KEY: secret:wdUPdCShQFSAkQMNDFbpc0NVhE3oA3F0iosCStvIHJth1MVjUTFGFdauMUHLBQS9vnbkvLBaQZ7ygERs2if5Sbjtsj7cq+Qyvsx6c1OONIIC34tt8gRU14dcAQuCnSAQnpH0b9uyyemBq0iFaY7Z8c4+xkPvVkzqy1ubPCSDljWDMCm2xJ9E5ZOBH+boqtXJV28hURv9I/eNvAibnG94mC8TqcGxSjDt5IruXBFVS+HhbjWS50zVT+UjdX7xnnyt4TNVcongrWG3Lm0mZa2nHZSgKLLUIWCe3rD+WJkmu6/GTzXYZ7CO9gT0zrXTfIr5vBIPiAqfJf0TQwCuLTcj1g==
+
+  pgbackup:
+    image: alexanderjackson/pgbackup
+    tag: 20240908-0628
+    port: 80
+    replicas: 1
+    host: unapplicable
+    environment:
+      S3_BUCKET: postgres-backups-65ef5c
+      USERNAME: postgres
+      PASSWORD: secret:Byct+Bq3nUl3GNZktRRi0tdIT5xCQKpqzQhTQ7aTOIT0uuT6sp6ED2PveWP80qDLOSOnBBbsogaKPTAADGc04/K9q/KItG6M07t7oKBF2CmsYXgM4pP0u1wV/rUf0FSTJmzgNM3z3jXQRbfKdVl+pSHipFYFFUPcukMhXv+5mx7tjGWccYukUqLe4lCA28rifsXdiGgJXEOrPVMIm+WOLauLuS2ANIuM3cN+tgLR5lLRHDQc4zR8fIGMXU59yEM2izJZTuUpz6/EvqbSVh//6G+Pt6gH5eBQ3KfEzSB19I0ZdWIFVwhj2TC9kF7cbDYmI9PwSywC1Egz3UuAKArwew==
+      ROOT_DATABASE: postgres
+      DATABASE_HOST: 10.0.0.238
+      DATABASE_PORT: 5432