Summary:
D29916 introduced a feature that compressed tuples in the catcache. However, performance benchmarks revealed that the performance overhead of enabling TOAST compression was too high to justify for most use cases, so it is disabled by default.

PG15 added support for a new compression algorithm, lz4. In our testing, lz4 achieves the same compression ratios as the previous default algorithm (pglz), with almost zero performance overhead.

This diff does two things:
1.  Enables the catcache TOAST compression feature by default for tuples >2KB in size.
2. Changes the default TOAST compression algorithm from pglz to lz4 ([[ https://docs.aws.amazon.com/AmazonRDS/latest/PostgreSQLReleaseNotes/postgresql-versions.html#postgresql-version15 | this is in line with what other managed PostgreSQL providers do ]]).

Test Plan: Jenkins

Reviewers: myang

Reviewed By: myang

Subscribers: svc_phabricator, yql

Differential Revision: https://phorge.dev.yugabyte.com/D41207