Add notifications feature and update feature flags

This update includes creating new files for the notifications feature along with adding two feature flags for enabling notifications and realtime notifications. All the code and package dependencies required for the notifications functionality have been added. The 'pnpm-lock.yaml' has also been updated due to the inclusion of new package dependencies.

apps/web/supabase/migrations/20221215192558_schema.sql

@@ -1969,6 +1969,128 @@ execute on function public.upsert_order (
   jsonb
 ) to service_role;
 
+/**
+ * -------------------------------------------------------
+ * Section: Notifications
+ * We create the schema for the notifications. Notifications are the notifications for an account.
+ * -------------------------------------------------------
+ */
+create type public.notification_channel as enum ('in_app', 'email');
+create type public.notification_type as enum ('info', 'warning', 'error');
+
+create table if not exists public.notifications (
+  id bigint generated always as identity primary key,
+  account_id uuid not null references public.accounts(id) on delete cascade,
+  type public.notification_type not null default 'info',
+  body varchar(5000) not null,
+  link varchar(255),
+  entity_id text,
+  entity_type text,
+  channel public.notification_channel not null default 'in_app',
+  language_code varchar(10) not null default 'en',
+  dismissed boolean not null default false,
+  expires_at timestamptz default (now() + interval '1 month'),
+  created_at timestamptz not null default now()
+);
+
+comment on table notifications is 'The notifications for an account';
+
+comment on column notifications.account_id is 'The account the notification is for (null for system messages)';
+
+comment on column notifications.type is 'The type of the notification';
+
+comment on column notifications.body is 'The body of the notification';
+
+comment on column notifications.link is 'The link for the notification';
+
+comment on column notifications.entity_id is 'The entity ID for the notification';
+
+comment on column notifications.entity_type is 'The entity type for the notification';
+
+comment on column notifications.channel is 'The channel for the notification';
+
+comment on column notifications.language_code is 'The language code for the notification';
+
+comment on column notifications.dismissed is 'Whether the notification has been dismissed';
+
+comment on column notifications.expires_at is 'The expiry date for the notification';
+
+comment on column notifications.created_at is 'The creation date for the notification';
+
+-- Open up access to order_items table for authenticated users and service_role
+grant
+select, update
+  on table public.notifications to authenticated,
+  service_role;
+
+grant insert on table public.notifications to service_role;
+
+-- enable realtime
+alter
+  publication supabase_realtime add table public.notifications;
+
+-- Indexes
+-- Indexes on the notifications table
+
+-- index for selecting notifications for an account that are not dismissed and not expired
+create index idx_notifications_account_dismissed on notifications(account_id, dismissed, expires_at);
+
+-- RLS
+alter table public.notifications enable row level security;
+
+-- SELECT(notifications):
+-- Users can read notifications on an account they are a member of
+create policy notifications_read_self on public.notifications for
+select
+  to authenticated using (
+    account_id = (
+      select
+        auth.uid ()
+    )
+    or has_role_on_account (account_id)
+  );
+
+-- UPDATE(notifications):
+-- Users can set notifications to read on an account they are a member of
+create policy notifications_update_self on public.notifications for
+update
+  to authenticated using (
+    account_id = (
+      select
+        auth.uid ()
+    )
+    or has_role_on_account (account_id)
+  );
+
+-- Function "kit.update_notification_dismissed_status"
+-- Make sure the only updatable field is the dismissed status and nothing else
+create or replace function kit.update_notification_dismissed_status()
+returns trigger
+set search_path to ''
+as $$
+begin
+    old.dismissed := new.dismissed;
+
+    if (new is distinct from old) then
+         raise exception 'UPDATE of columns other than "dismissed" is forbidden';
+    end if;
+
+    return old;
+end;
+$$ language plpgsql;
+
+-- add trigger when updating a notification to update the dismissed status
+create trigger update_notification_dismissed_status before update on public.notifications for each row
+execute procedure kit.update_notification_dismissed_status();
+
+/**
+ * -------------------------------------------------------
+ * Section: Slugify
+ * We create the schema for the slugify functions. Slugify functions are used to create slugs from strings.
+ * We use this for ensure unique slugs for accounts.
+ * -------------------------------------------------------
+ */
+
 -- Create a function to slugify a string
 -- useful for turning an account name into a unique slug
 create
@@ -2131,6 +2253,13 @@ create trigger on_auth_user_created
 after insert on auth.users for each row
 execute procedure kit.setup_new_user ();
 
+/**
+ * -------------------------------------------------------
+ * Section: Functions
+ * We create the schema for the functions. Functions are the custom functions for the application.
+ * -------------------------------------------------------
+ */
+
 -- Function "public.create_team_account"
 -- Create a team account if team accounts are enabled
 create