feat(table): add configurable autovacuum settings for outbox tables

[OpenSourceAlchemist]

Description

Add configurable autovacuum settings to outbox tables via ALTER TABLE SET (...).

Outbox tables have high churn as events are inserted and then processed/deleted.
Default PostgreSQL autovacuum settings (scale_factor=0.2) can lead to table bloat
and performance degradation.

Changes

• Apply autovacuum settings on table creation (on by default)
• All 5 thresholds are configurable via options
• Opt-out with autovacuum: false
• Add --no-autovacuum CLI flag to outboxify

API

DB.pgt_outbox_setup(:accounts,
  autovacuum: true,                              # default: on
  autovacuum_vacuum_scale_factor: 0,             # default
  autovacuum_vacuum_threshold: 50,               # default
  autovacuum_analyze_scale_factor: 0,            # default
  autovacuum_analyze_threshold: 50,              # default
  autovacuum_vacuum_cost_delay: 0                # default
)

Closes #29

[bougyman]

Looks solid. Make it sew