feat: add more options for when to make proxied messages silent

crates/migrate/data/migrations/54.sql

@@ -0,0 +1,11 @@
+-- database version 54
+-- change suppress notifications server config to an enum
+
+alter table servers 
+    alter column suppress_notifications drop default,
+    alter column suppress_notifications type int 
+        using case when suppress_notifications then 1 else 0 end,
+    alter column suppress_notifications set default 0,
+    add constraint suppress_notifications_check check (suppress_notifications = ANY (ARRAY[0,1,2,3]));
+
+update info set schema_version = 54;