Set default compression as the superior lz4 algorithm.

This one is faster and achieves better compression than pglz,
but is only available in PostgreSQL starting in version 14
(which isn't a concern for us since we'll be using latest stable
to start with.)

deepwell/migrations/20220906103252_deepwell.sql

@@ -234,7 +234,7 @@ CREATE TYPE page_revision_change AS ENUM (
 -- but since we can't we'll just verify the hash length.
 CREATE TABLE text (
     hash BYTEA PRIMARY KEY,
-    contents TEXT COMPRESSION pglz NOT NULL,
+    contents TEXT NOT NULL,
 
     CHECK (length(hash) = 16)  -- KangarooTwelve hash size, 128 bits
 );

install/files/postgres/init/02-seed.sql

@@ -9,6 +9,7 @@ SET statement_timeout = 0;
 SET lock_timeout = 0;
 SET idle_in_transaction_session_timeout = 0;
 SET client_encoding = 'UTF8';
+SET default_toast_compression=lz4;
 SET standard_conforming_strings = on;
 SELECT pg_catalog.set_config('search_path', '', false);
 SET check_function_bodies = false;