Ignore non-versioned Features when generating outdated report

[joshspicer]

Made a couple changes to the outdated command.

• Addresses devcontainer outdated gives incorrect current version information for some deprecated features #712 by omitting the deprecated "short-hand" Feature syntax from the output of outdated.
  • This is a bit opinionated, but my reasoning here is that - since there is no way for the user to alter these Feature versions (they're "held back" to the major version from when they were deprecated) - it doesn't make sense to surface in outdated.
  • Omitting these Features from outdated will subsequently cause the dependabot integration to not consider them for version updates, which is already being done as an exceptional case.
• Updates to getRef() to better filter out non-OCI Features, namely "local Features".
• Fix a sorting bug that caused --output-format text to exit unsuccessfully if a "local Feature" was present in the config.
  • Added a test to exercise that code path

[chrmarti]

LGTM!

[samruddhikhandale]

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