add per-pr ci

[Daniel Franklin]

Add to the deploy tool to

• setup a single shared staging database (at least for now).
• create staging secrets and copy into each ns
• make deploy tool deploy into staging per-pr namespace in cluster
• add option to deploy tool to cleanup from cluster
• deploy s3 bucket and cf distribution for app
• add option to cleanup bucket & dist
• wire into GitHub actions
• ideally configure cert-manager to issue wildcards to get around 50 issuance per week limit
• copy vanity map url behavior to staging distribution
• debug intermittent "relation does not exist" database error

[Daniel Franklin]

what if we omit the schema from migrations and set the default schema somehow if postgres supports that?

then we could have per-pr tables but a single database, user, and connection pool