Connect-sdk

* HTTP timeout request to Connect platform should be not less than 300 seconds.
* Accept Usage File is sending wrong parameter in post request.
* Usage processor filter "product__id" is not filtering by product id.
* All fields accept null to avoid parsing errors.

* external_id is sometimes returned as an integer by Connect API, which breaks Python SDK parsing.

* Add custom loggers to the automation classes, that automatically add relevant info of the request being processed. Legacy global logger still working in order to have a context-independent logger.
* Get product templates and configuration params.
* Put each model in its own Python file, to reduce the chance of having circular references on imports.
* Tier requests are not filtering by product id by default.
* Fulfillment assignee not receiving the right type.

* Fixed bugs when listing and working with usage files.
* Directory module.
* Models updated with new fields from v17.

* Catch generic `Exception` on dispatch and skip request instead of aborting execution.
* Insert request id (both tier config or fulfillment) on logs.
* Fix: The `configuration.product.id` and `configuration.account.id` filters do not work as expected. Reverting to `configuration__product__id` and `configuration__account__id`.
* Fix: The SDK was not parsing dropdown value choices correctly.
* Fix: Added `period` field to item.
* Changed documentation theme to sphinx_rtd_theme.

* Fix: Documentation of `FulfillmentAutomation` and `TierConfigAutomation`, and added documentation for `ActivationTemplateResponse` and `ActivationTileResponse`.
* Fix: Return value of `Fulfillment.needs_migration` when migration_info exists but has no value.
* Fix: Some requests are returning params with null values, so support for it has been added.
* Fix: Ensure that the response of an HTTP request is a valid string.
* Fix: Checking for validity of conversation object was done on approval, but not on fail, inquire nor skip.
* Fix: Deserialization of `ServerErrorResponse` in `ApiClient._check_and_pack_response`.