Delete temp files when no longer needed

[eerhardt]

Today, we generate temporary files and bind mount them to local containers. This allows Aspire to configure the container. However, these temporary files never get deleted.

For example:

aspire/src/Aspire.Hosting.PostgreSQL/PostgresBuilderExtensions.cs

Lines 154 to 166 in d388901

	.WithBindMount(Path.GetTempFileName(), "/pgadmin4/servers.json")
	.WithHttpHealthCheck("/browser")
	.ExcludeFromManifest();
	builder.ApplicationBuilder.Eventing.Subscribe<AfterEndpointsAllocatedEvent>((e, ct) =>
	{
	var serverFileMount = pgAdminContainer.Annotations.OfType<ContainerMountAnnotation>().Single(v => v.Target == "/pgadmin4/servers.json");
	var postgresInstances = builder.ApplicationBuilder.Resources.OfType<PostgresServerResource>();
	var serverFileBuilder = new StringBuilder();
	using var stream = new FileStream(serverFileMount.Source!, FileMode.Create);
	using var writer = new Utf8JsonWriter(stream);

We should have a service for doing this that gets cleaned up on exit. @karolz-ms says:

I can imagine us having the capability for Containers where you can say "here is a blob of JSON that I need to appear as file inside the container, under this path". Sort of like Kubernetes ConfigMaps.