chore: move migrations to rust

also adds some basic test seed data

PluralKit.Core/Database/Migrations/9.sql

@@ -1,32 +0,0 @@
--- SCHEMA VERSION 9: 2020-08-25 --
--- Adds support for member groups.
-
-create table groups (
-    id int primary key generated always as identity,
-    hid char(5) unique not null,
-    system int not null references systems(id) on delete cascade,
-    
-    name text not null,
-    display_name text,
-    description text,
-    icon text,
-    
-    -- Description columns follow the same pattern as usual: 1 = public, 2 = private
-    description_privacy integer check (description_privacy in (1, 2)) not null default 1,
-    icon_privacy integer check (icon_privacy in (1, 2)) not null default 1,
-    list_privacy integer check (list_privacy in (1, 2)) not null default 1,
-    visibility integer check (visibility in (1, 2)) not null default 1,
-
-    created timestamp with time zone not null default (current_timestamp at time zone 'utc')
-);
-
-create table group_members (
-    group_id int not null references groups(id) on delete cascade,
-    member_id int not null references members(id) on delete cascade,
-    primary key (group_id, member_id)
-);
-
-alter table systems add column group_list_privacy integer check (group_list_privacy in (1, 2)) not null default 1;
-update systems set group_list_privacy = member_list_privacy;
-
-update info set schema_version = 9;