Bump version to 2.3.2

Merge branch 'pglogical2-fix-revert' into REL2_x_STABLE

This reverts several problematic changes introduced between 2.2.2 and
2.3.0.

pglogical_create_subscriber: Fix for PostgreSQL 12

Instead of writing to recovery.conf, append to postgresql.auto.conf.
This follows the same logic as pg_basebackup -R.

Include package installation instructions

Test: Modify row_filter expected

output - for a modified error in PG 10.

Switch to MessageContext after SPI calls

Modify tests for Postgres-XL subscriber

Create default pglogical extension.
Version 2.0.0 no more has a direct extension sql file, so some tests were failing. Fixed those.

Fix previous commit

Better way of ignoring pglogical internal objects in dependency checks

Those should be handled by postgres, not by pglogical, but the filtering
code required pglogical.depend table to be present. That table is not
present in case of extension upgrades. New code just checks relation
schema and compares it to pglogical one.

Doc improvements around XL