feat: migrate environment variables to plugin properties

Standardize how environment variables are migrated to properties during
install triggers and migrate all remaining DOKKU_* config vars to their
appropriate plugin properties.

Adds a reusable MigrateConfigToProperties() function in the common
package with Transform callback and ListProperty support, plus a
migrate-config-to-property subcommand for the prop binary so shell
plugins can use the same code path.

Migrated variables and their new property owners:
- DOKKU_APP_PROXY_TYPE/DOKKU_PROXY_TYPE → proxy type
- DOKKU_DISABLE_PROXY → proxy disabled
- DOKKU_PROXY_PORT → ports proxy-port
- DOKKU_PROXY_SSL_PORT → ports proxy-ssl-port
- DOKKU_APP_RESTORE → ps restore
- DOKKU_SKIP_DEPLOY → ps skip-deploy
- DOKKU_START_CMD → ps start-cmd
- DOKKU_DOCKERFILE_START_CMD → ps dockerfile-start-cmd
- DOKKU_DISABLE_APP_AUTOCREATION → apps disable-autocreation
- DOKKU_APP_SHELL → scheduler shell
- DOKKU_SKIP_CLEANUP → builder skip-cleanup
- DOKKU_CHECKS_DISABLED → checks disabled
- DOKKU_CHECKS_SKIPPED → checks skipped
- DOKKU_CHECKS_WAIT → checks wait
- DOKKU_CHECKS_TIMEOUT → checks timeout
- DOKKU_CHECKS_ATTEMPTS → checks attempts
- DOKKU_DEFAULT_CHECKS_WAIT → checks default-wait
- DOKKU_SKIP_ALL_CHECKS → checks disabled (legacy)
- DOKKU_SKIP_DEFAULT_CHECKS → checks skipped (legacy)

Also refactors existing bespoke migration loops in scheduler, ports, ps,
builder, and nginx-vhosts plugins to use the standardized utility.

Removes DOKKU_PARALLEL_ARGUMENTS from documentation (unused in core).
Deprecates fn-migrate-config-to-property bash function.

closes #1558

docs/deployment/application-deployment.md

@@ -143,11 +143,11 @@ dokku letsencrypt:cron-job --add
 
 ### Skipping deployment
 
-If you only want to rebuild and tag a container, you can skip the deployment phase by setting `$DOKKU_SKIP_DEPLOY` to `true` by running:
+If you only want to rebuild and tag a container, you can skip the deployment phase by setting the `skip-deploy` property to `true`:
 
 ``` shell
 # on the Dokku host
-dokku config:set ruby-getting-started DOKKU_SKIP_DEPLOY=true
+dokku ps:set ruby-getting-started skip-deploy true
 ```
 
 ### Redeploying or restarting

docs/deployment/zero-downtime-deploys.md

@@ -40,17 +40,17 @@ Defaults to `60`.
 
 You can set the `stop-timeout-seconds` property on the `ps` plugin to change this value (default: `30`). See the [process management documentation](/docs/processes/process-management.md#changing-process-management-settings) for more information.
 
-## Configuring check settings using the `config` plugin
+## Configuring check settings
 
-There are certain settings that can be configured via environment variables:
+There are certain settings that can be configured via the `checks` plugin properties:
 
-- `DOKKU_DEFAULT_CHECKS_WAIT`: (default: `10`) If no user-defined checks are specified - or if the process being checked is not a `web` process - this is the period of time Dokku will wait before checking that a container is still running.
+- `default-wait`: (default: `10`) If no user-defined checks are specified - or if the process being checked is not a `web` process - this is the period of time Dokku will wait before checking that a container is still running. Set globally via `dokku checks:set --global default-wait <value>`.
 
-The following settings may also be specified in the `app.json` file, though are available as environment variables in order to ease application reuse.
+The following settings may also be specified in the `app.json` file, though are available as properties in order to ease application reuse.
 
-- `DOKKU_CHECKS_WAIT`: (default: `5`) Wait this many seconds for the container to start before running checks.
-- `DOKKU_CHECKS_TIMEOUT`: (default: `30`) Wait this many seconds for each response before marking it as a failure.
-- `DOKKU_CHECKS_ATTEMPTS`: (default: `5`) Number of retries for to run for a specific check before marking it as a failure
+- `wait`: (default: `5`) Wait this many seconds for the container to start before running checks. Set via `dokku checks:set <app> wait <value>`.
+- `timeout`: (default: `30`) Wait this many seconds for each response before marking it as a failure. Set via `dokku checks:set <app> timeout <value>`.
+- `attempts`: (default: `5`) Number of retries for to run for a specific check before marking it as a failure. Set via `dokku checks:set <app> attempts <value>`.
 
 ## Skipping and Disabling Checks