pgmoon support automatic master-slave switch

[liukaiyuliukaiyu]

Whether pgmoon can support automatic master-slave switching? when the primary database fails，the primary/secondary switchover is detected through the database protocol, and the underlying layer can be adjusted to connect to the new primary database.

[leafo]

same answer as here: https://github.com/leafo/pgmoon/issues/129

no plans to add layers above the database connection logic