refactor: deprecate proxy-configure-ports plugin trigger in favor of ports-configure

This also rewrites the logic to be in golang, which will make it easier to refactor portions of it to use the property system going forward.

docs/development/plugin-triggers.md

@@ -1256,6 +1256,21 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 # TODO
 ```
 
+### `ports-configure`
+
+- Description: Configures the port mapping
+- Invoked by: `internally triggered by proxy plugins`
+- Arguments: `$APP`
+- Example:
+
+```shell
+#!/usr/bin/env bash
+
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+# TODO
+```
+
 ### `ports-dockerfile-raw-tcp-ports`
 
 > Warning: This trigger is for internal use and will be removed in a future release. Do not use it in your codebase.
@@ -1934,6 +1949,8 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 
 ### `proxy-configure-ports`
 
+> Warning: Deprecated, please use `ports-configure` instead
+
 - Description: Configures the port mapping
 - Invoked by: `internally triggered by proxy plugins`
 - Arguments: `$APP`