Add a new command for annotating image digests for EOL

[NikolaMilosavljevic]

Contributes to: #1201

The work is being split into smaller PRs to aid in review process.

Some notes:

• We allow two scenarios for annotations - with and without checking for existing annotations.
• Check for existing annotations relies on oras discover command and its stdout. This will likely be updated once Oras completed the work on managed library.
• oras login command was not needed, as we already do docker login
• We do not fail if we fail to annotate one digest, we proceed until the end and log all failures, at which point we fail the command.
• There are 3 tests right now. We could add more later.

JSON file format (with sample dates):

{
  "eolDate": "2024-05-27",
  "eolDigests": [
    {
      "digest": "digest-value"
    },
    {
      "digest": "digest-value",
      "eolDate" : "2022-03-01"
    }
  ]
}

EOL data can be specified as a global value (optional) for all digests in the file. Each digest can have its own specific EOL date, which overrides the global value (if set).

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[NikolaMilosavljevic]

Hmm, some test failures on Linux. This worked fine on Windows.

Working on a fix.

[mthalman]

Consider using force as the name of the option instead. It's more commonly used.

[NikolaMilosavljevic]

force was the option I also considered. Yeah, it makes sense to use it - will fix.

[NikolaMilosavljevic]

Fixed with 12fe0a4

[mthalman]

I learned from @lbussell that these #nullable directives at the end of the file aren't needed. The scope of #nullable enable only applies to the file.

[NikolaMilosavljevic]

Fixed with 12fe0a4

[mthalman]

Unnecessary

[NikolaMilosavljevic]

Right, forgot to remove - thanks.

[NikolaMilosavljevic]

Fixed with 12fe0a4