Add system and member privacy support

PluralKit.Core/Migrations/2.sql

@@ -0,0 +1,13 @@
+-- We're doing a psuedo-enum here since Dapper is wonky with enums
+-- Still getting mapped to enums at the CLR level, though.
+-- https://github.com/StackExchange/Dapper/issues/332 (from 2015, still unsolved!)
+-- 1 = "public"
+-- 2 = "private"
+-- not doing a bool here since I want to open up for the possibliity of other privacy levels (eg. "mutuals only")
+alter table systems add column description_privacy integer check (description_privacy in (1, 2)) not null default 1;
+alter table systems add column member_list_privacy integer check (member_list_privacy in (1, 2)) not null default 1;
+alter table systems add column front_privacy integer check (front_privacy in (1, 2)) not null default 1;
+alter table systems add column front_history_privacy integer check (front_history_privacy in (1, 2)) not null default 1;
+alter table members add column member_privacy integer check (member_privacy in (1, 2)) not null default 1;
+
+update info set schema_version = 2;