Add archiving event publication completion mode

[odrotbohm]

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The recently introduced delete completion mode provides an alternative to the default updating mode. It allows keeping the number of event publication entries low at the expense of completed publications not being accessible. A new archiving mode could augment the deletion of the original entry with an insert into a publication archive.

Required steps

• Augment CompletionMode enum with ARCHIVING value
• In JDBC, Add schema files that create a separate database table. Adapt SQL statement creation to let the completion and the lookup of completed publications target that new archive table.
• Similar approaches for MongoDB, Neo4j and JPA