feat: allow users to bind to all interfaces when a proxy is enabled

- use a plugin trigger to see whether we should bind to all interfaces
- create a generic way of setting properties for a plugin
- migrate proxy-enabled to the new network property "bind-all-interfaces"
- add network:set subcommand

plugins/network/network.go

@@ -12,6 +12,16 @@ import (
 	sh "github.com/codeskyblue/go-sh"
 )
 
+// ValidProperties is a map of all valid network properties
+var ValidProperties = map[string]bool{
+	"bind-all-interfaces": true,
+}
+
+// DefaultPropertyValues is a map of all valid network properties with corresponding default property values
+var DefaultPropertyValues = map[string]string{
+	"bind-all-interfaces": "false",
+}
+
 // BuildConfig builds network config files
 func BuildConfig(appName string) {
 	err := common.VerifyAppName(appName)
@@ -147,6 +157,14 @@ func GetContainerPort(appName string, procType string, isHerokuishContainer bool
 	return port
 }
 
+// GetDefaultValue returns the default value for a given property
+func GetDefaultValue(property string) string {
+	if ValidProperties[property] {
+		return DefaultPropertyValues[property]
+	}
+	return ""
+}
+
 // HasNetworkConfig returns whether the network configuration for a given app exists
 func HasNetworkConfig(appName string) bool {
 	appRoot := strings.Join([]string{common.MustGetEnv("DOKKU_ROOT"), appName}, "/")