Publish CM3 EoL (#4232)

* Update screensaver.adoc

Broken link fix

* EoL for CM3 plus updates to docs (#4226)

EoL for CM3; corrected info for chips used and converted to table for direct comparison; restructured summaries of each CM for clarity; for consistency, added memory information for 3 and 3+; corrected instructions for CM5 accessories.

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Co-authored-by: Jeunese <jeunese.payne@raspberrypi.com>

Author: katshann-raspberry