agent: enforce a soft limit on the number of bindings per task

[psFried]

Flow can only handle so many bindings for a given task. We don't precisely know what that number is, and it varies somewhat from task to task, but suffice to say that there's such a thing as too many. We'd like to prevent users from publishing tasks that have more than that number of bindings. Regardless of the specific maximum number we pick, there's existing tasks that already have more bindings than that. The logic for enforcing this maximum must permit existing tasks to maintain their current bindings, even if it's over the maximum. In that case, it should only prevent net new bindings from being added.

We also anticipate needing to adjust this limit on more of a case-by-case basis. So we should store the limit in the database (probably next to the quotas on the tenants table).

Bikeshedding: what number to pick as the default limit

[dyaffe]

It would be really nice if what we pick doesn't prevent the standard netsuite case from working...