Pymagento

* Allow to override `Magento.PAGE_SIZE` when creating a client with the `batch_page_size` keyword argument
* Remove `Magento.TOKEN_LIFETIME`; it wasn’t used for anything

* Uniformize the signatures of functions that return a generator. The following functions now support a `limit`:
`get_categories` (3), `get_stock_source_links`, `get_sources`. All these function now pass their additional keyword
arguments to the internal `self.get_paginated` call.

* Add `get_source`, `get_sources`, `save_source`

* Support SKUs that contain slashes

* Pass additional keyword arguments in `Magento()` to the underlying `APISession()` constructor
* Remove the `verbose` optional keyword option as well as the `log_response` parameter. Instead, use the `DEBUG` level
for logging. Instead of setting these variables to `True`, set your logger level to `DEBUG`.

* Fix `coerce_as` for list values in `get_custom_attribute`. The function now correctly gets each individual value
rather than the whole list.
* Fix type hint for list values in `get_custom_attribute`