## Problem
We currently have this code duplicated across different PG versions.
Moving this to an extension would reduce duplication and simplify
maintenance.
## Summary of changes
Moving the LastWrittenLSN code from PG versions to the Neon extension
and linking it with hooks.
Related Postgres PR: https://github.com/neondatabase/postgres/pull/590
Closes: https://github.com/neondatabase/neon/issues/10973
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Co-authored-by: Tristan Partin <tristan@neon.tech>
Seems nice to keep all these together. This also provides a nice place
for a README file to describe the compute image build process. For
now, it briefly describes the contents of the directory, but can be
expanded.
