add whitelisting

[nick-mccoy]

Since the Stripe events stream has a ton of nested fields, it can cause the number of unique fields of a batch of records to exceed 1600. To mitigate this, this PR introduces a new, optional config field called whitelist_map that takes the following form:

{
   <stream_name>: [
      [<field_1_breadcrumb>],
      [<field_2_breadcrumb>],
      ...
      [<field_n_breadcrumb>]
   ]
}

for example:

{
    "events": [
        ["data", "object", "customer"],
        ["data", "object", "id"],
        ["data", "object", "plan", "id"],
        ["data", "object", "plan", "amount"],
        ["data", "object", "plan", "created"],
        ["data", "object", "plan", "interval"],
        ["data", "object", "plan", "name"],
        ["data", "object", "plan", "object"],
        ["data", "object", "created"],
        ["data", "object", "start"],
        ["data", "object", "quantity"],
        ["data", "object", "status"],
        ["data", "object", "subscription"],
        ["data", "object", "amount"],
        ["data", "object", "canceled_at"],
        ["data", "object", "payment"],
        ["data", "object", "metadata", "email"],
        ["data", "object", "metadata", "orgid"],
        ["data", "previous_attributes", "plan", "created"],
        ["data", "previous_attributes", "plan", "id"],
        ["data", "previous_attributes", "plan", "name"],
        ["data", "previous_attributes", "status"],
        ["data", "previous_attributes", "plan", "object"],
        ["data", "previous_attributes", "quantity"],
        ["data", "previous_attributes", "plan", "amount"],
    ]
}

Note that all breadcrumbs should have more than one entry since top level fields can already be deselected by the user. The tap asserts that all breadcrumbs have a length > 1 and will therefore error if it receives a breadcrumb of length = 1.

[dmosorast]