Rm remaining refs to package manifest format

[adellape]

Remove/update places still referring to "package manifest format" support in 4.8.

Preview:

• Operator Framework packaging formats only details the bundle format now, but mentions removal of package manifest support in a NOTE in the intro, with a link to migration guide.
• No more references in Operator Framework glossary of common terms
• No more references in Managing custom catalogs
• Step 3 in Mirroring an Operator catalog has an IMPORTANT admonition about an edge case that needed to reference a step in the package manifest format version of the catalog mirroring steps. Since that section was removed, this admonition now links to the 4.7 docs to reference those instructions.

For reference, #34200 is a related PR for the 4.8 release notes.

[netlify]

✔️ Deploy Preview for osdocs ready!

🔨 Explore the source changes: 832df0c

🔍 Inspect the deploy log: https://app.netlify.com/sites/osdocs/deploys/60dd61a8f5318a0008b80b37

😎 Browse the preview: https://deploy-preview-34198--osdocs.netlify.app/openshift-enterprise/latest/operators/admin/olm-managing-custom-catalogs

[ahardin-rh]

Looks good! 🚀

[adellape]

/cherrypick enterprise-4.8

[openshift-cherrypick-robot]

@adellape: new pull request created: #34240

In response to this:

/cherrypick enterprise-4.8

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