Move native remote to just remote

It's just a remote builder, that will build whichever platform is asked
for, so let's remove the "native" part.

We'll also remove the service name from the builder name, so multiple
services can share the same builder.

lib/kamal/commands/builder.rb

@@ -19,7 +19,7 @@ class Kamal::Commands::Builder < Kamal::Commands::Base
     when config.builder.local? && config.builder.remote?
       multiarch_remote
     when config.builder.remote?
-      native_remote
+      remote
     else
       local
     end
@@ -29,8 +29,8 @@ class Kamal::Commands::Builder < Kamal::Commands::Base
     @native ||= Kamal::Commands::Builder::Native.new(config)
   end
 
-  def native_remote
-    @native ||= Kamal::Commands::Builder::Native::Remote.new(config)
+  def remote
+    @remote ||= Kamal::Commands::Builder::Remote.new(config)
   end
 
   def local

lib/kamal/commands/builder/remote.rb

@@ -1,4 +1,4 @@
-class Kamal::Commands::Builder::Native::Remote < Kamal::Commands::Builder::Native
+class Kamal::Commands::Builder::Remote < Kamal::Commands::Builder::Base
   def create
     chain \
       create_context,
@@ -27,7 +27,7 @@ class Kamal::Commands::Builder::Native::Remote < Kamal::Commands::Builder::Nativ
   end
 
   def context_hosts
-    context_host(builder_name_with_arch)
+    context_host(builder_name)
   end
 
   def config_context_hosts
@@ -37,11 +37,7 @@ class Kamal::Commands::Builder::Native::Remote < Kamal::Commands::Builder::Nativ
 
   private
     def builder_name
-      "kamal-#{config.service}-native-remote"
-    end
-
-    def builder_name_with_arch
-      "#{builder_name}-#{remote_arch}"
+      "kamal-remote-#{remote_arch}"
     end
 
     def platform
@@ -49,16 +45,15 @@ class Kamal::Commands::Builder::Native::Remote < Kamal::Commands::Builder::Nativ
     end
 
     def create_context
-      docker :context, :create,
-        builder_name_with_arch, "--description", "'#{builder_name} #{remote_arch} native host'", "--docker", "'host=#{remote_host}'"
+      docker :context, :create, builder_name, "--description", "'#{builder_name} host'", "--docker", "'host=#{remote_host}'"
     end
 
     def remove_context
-      docker :context, :rm, builder_name_with_arch
+      docker :context, :rm, builder_name
     end
 
     def create_buildx
-      docker :buildx, :create, "--name", builder_name, builder_name_with_arch, "--platform", platform
+      docker :buildx, :create, "--name", builder_name, builder_name, "--platform", platform
     end
 
     def remove_buildx