[QCR][Final] Clean up eng/common/templates/post-build folder

- It's silly that there's no consistency between parameter names in different templates
ie. "[StageLabel](https://github.com/dotnet/arcade/blob/master/eng/common/templates/steps/publish-logs.yml#L2)" vs "[stageName](https://github.com/dotnet/arcade/pull/4344/files#diff-fb459e4b4cccf45ce665b4bc780235c2R7)"
- The folder name "post-build" doesn't really make sense because

- if it really means "post-build", then there's other things that are post-build, like tests

- it's all in the azure build pipeline now so there's not really a post-build thing happening

I'd prefer a name like "release"

- It feels like there's this pattern for templates under `/eng/common/templates` where templates are stored in the folder which represents the [type of template reference](https://docs.microsoft.com/en-us/azure/devops/pipelines/yaml-schema?view=azure-devops&tabs=schema#stage-templates) they are, and then there's this "post-build" folder where there's a completely different convention for folder naming.

We should clean up our templates (parameter usage, filenames, etc...) and follow a defined convention rather than this wild west of template names / locations. The difficulty, at this point, is doing so without making it a breaking change.