add concept for OCI Artifact

[sajayantony]

Preview link - https://deploy-preview-238--oras-project.netlify.app/docs/concepts/artifact

[SteveLasker]

Overall, looks great with feedback.
Biggest concern is the example for multiple SBOMs in an index.
Minor nit/question. What is the formatting guidance? This PR uses the 80 character rule, as opposed to sentences on separate lines for easier commenting.

[sajayantony]

Good question. I generally preffer the 80 character limit since its easier to read without rendering, but can change it whatever the guidance /cc @FeynmanZhou is this called out somewhere?

[TerryHowe]

What is the formatting guidance? This PR uses the 80 character rule, as opposed to sentences on separate lines for easier commenting.

I don't know if we have an official standard, but I prefer https://sembr.org/

[sajayantony]

@FeynmanZhou @toddysm @shizhMSFT PTAL.

[SteveLasker]

Good question. I generally preffer the 80 character limit since its easier to read without rendering, but can change it whatever the guidance /cc @FeynmanZhou is this called out somewhere?

The benefit of using separate lines for each sentence is you can scope a comment, make a PR to a specific line.
I suppose 80 characters and 1 sentence per line aren't mutually exclusive, but we should adopt these to simplify reading/commenting and subsequent PRs.

[shizhMSFT]

LGTM