Package authoring guidance and best practices

[johnbelamaric]

The documentation covers the mechanics but doesn't provide guidance on authoring packages. Some simple questions that are immediately faced by a package author (some are covered in the app epic, I believe):

1. Should I set the namespace in resources? If so, to what?
2. Should I separate resources into separate yaml files as a best practice? Is there a naming convention I should follow as a best practice?
3. Should I use "example" for all my placeholders?
4. Does file naming matter for ordering, a la kubectl apply -f <dir>?
5. Is there a convention recommended for deployment labels? Should the values be "example", or the app-name? Will the label values be changed to match the package name when it's instantiated?
6. Is there a convention around labeling resources with the package information and version?
7. In the common case of a Service/Deployment pair, can we automatically validate the selectors match?
8. Should my package create a namespace?
9. Are there specific tagging conventions that should be used so that Porch UI will show a package? Or is there a best practice for tagging?