TreeView sort and presentation

[hamlinmark]

Nice extension.

1. Services in the Tree View appear in random order, alphabetical would be good.

2. We have multiple compose files to break up a large amount of microservices into logical groups. This works fine in the extension once compose filenames are added in vscode settings. But it would be great if these appeared as tree nodes under the workspace to collect the services defined in the file. Combined with the random sorting, it's a little messy.