A simple basic API

Included: removal of remains of GraphQL adaptation. IMO the after/before
behaviour is actually pretty badly defined if entities can be deleted, and
delivers complexity trying to fix behaviour that users generally expect
and are comfortable coping with. Of course special cases _do_ justify
going extra length to provide consistent pagination.

sql/tasks/list.sql

@@ -1,14 +1,14 @@
+
 SELECT 
     id,
+    owner,
     name,
     notes,
     schedule,
-    min_frequency,
-    max_frequency,
     created_at
 FROM
     tasks
 WHERE
-    owner = $1 AND ($2 IS NULL OR id > $2) AND ($3 IS NULL OR id < $3)
-ORDER BY created_at ASC
-LIMIT $4;
+    owner = $1
+ORDER BY created_at ASC, id ASC
+LIMIT $2 OFFSET $3;