[CI] Add backup_build workflow to Buildkite/GH Actions
Summary:
This was previously handled as part of the "Services CI" workflow which will be deprecated later in this stack. This diff allows us to increase concurrency as we move over to the autoscaling EC2 instances.
Differences on Buildkite side:
- We use the actual shell command (cd services && docker-compose build --no-cache backup-server) instead of yarn build-backup-service because the autoscaling instances are intended to be as minimal as possible and don't include node, yarn, etc.
- We use the --no-cache flag to force a new complete build on each run. The previous "Services CI" workflow depended heavily on caches, because running 3-4 complete builds would take a long time. Now we can separate these out and take advantage of the concurrency provided by the autoscaling instances.
Test Plan:
Buildkite: Copy/pasted from what I have in the Buildkite GUI that has been "active" for the last 2-3 days without issue.
GitHub: Will see what happens when it lands, but fairly confident it should be good to go.
Reviewers: def-au1t, palys-swm, yayabosh, karol-bisztyga
Reviewed By: palys-swm, yayabosh, karol-bisztyga
Subscribers: karol-bisztyga, ashoat, Adrian
Differential Revision: https://phab.comm.dev/D4389