Introduces the Entry and Attachment types that the storage plugin will use as the source of truth for named storage volumes, replacing the colon-delimited mount strings stored under docker-options. Entries persist as JSON under config/storage/entries and validate against scheduler-specific rules; attachments persist via the property list and capture how an app uses an entry. The legacy migration name synthesizer is also added so existing colon-form mounts can converge on a deterministic legacy- entry name. Existing storage commands are unchanged in this commit.
Without this, building Dokku on a newer operating system will result in binaries that do not work on older systems. The environment variables were only being set when building in docker, which has not been used in the release workflow for a while.
The big feature missing from deployments today is healthchecks, which require extra parsing of the app.json format since the healthchecks there aren't immediately serializable to kubernetes deployment healthchecks.
Other smaller missing functionality from the existing OSS kubernetes scheduler are:
- The ability to set custom pod annotations
- The ability to set custom deployment annotations
- The ability to mount volumes
Exposing these pieces of functionality will come at a later date, if at all.
