chore: remove deprecated proxy-ports functions and and plugin subcommands

These were deprecated in 0.31.0 in favor of the ports plugin.

docs/appendices/0.32.0-migration-guide.md

@@ -21,3 +21,9 @@
 ## Removals
 
 - ARM support has been removed. Users of ARM installations on platforms such as the Raspberry PI should consider migrating to ARM64. ARM64 will continue to be supported by Dokku, and there are no plans to remove support for ARM64.
+- The following proxy-port related code has been removed. It is replaced by the `ports` plugin and it's related plugin triggers.
+    - `proxy:ports-*` commands
+    - `proxy-configure-ports` plugin trigger
+    - `common#get_available_port()`
+    - `common#get_dockerfile_exposed_ports()`
+    - `common#get_exposed_ports_from_image()`

docs/development/plugin-triggers.md

@@ -2194,24 +2194,6 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 # TODO
 ```
 
-### `proxy-configure-ports`
-
-> [!WARNING]
-> Deprecated, please use `ports-configure` instead
-
-- 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
-```
-
 ### `proxy-disable`
 
 - Description: Disables the configured proxy implementation for an app