Add PostgreSQL 14 support.

There are no code changes from PostgreSQL 13 so simply add the new version.

Add CATALOG_VERSION_NO_MAX to allow the catalog version to "float" during the PostgreSQL beta/rc period so new pgBackRest versions are not required when the catalog version changes.

Update the integration tests to handle new PostgreSQL startup messages.

src/postgres/interface.c

@@ -78,6 +78,16 @@ typedef struct PgInterface
 
 static const PgInterface pgInterface[] =
 {
+    {
+        .version = PG_VERSION_14,
+
+        .controlIs = pgInterfaceControlIs140,
+        .control = pgInterfaceControl140,
+        .controlVersion = pgInterfaceControlVersion140,
+
+        .walIs = pgInterfaceWalIs140,
+        .wal = pgInterfaceWal140,
+    },
     {
         .version = PG_VERSION_13,