feat: expose retry params in partition via api

[pawel-kmiecik]

This PR:

• adds parameters to control the retry-mechanism behaviour for partition_via_api:

    retries_initial_interval: [int] = None,
    retries_max_interval: Optional[int] = None,
    retries_exponent: Optional[float] = None,
    retries_max_elapsed_time: Optional[int] = None,
    retries_connection_errors: Optional[bool] = None,

• adds tests that check using them according to defaults

[badGarnet]

this is effectively create a wrapper for the unstructured-client interface so my question for the design is why do we need to add this to the document processing project. This creates ambiguous boundary of the projects (is this just document processing or does it also include client interfaces to a remote service, that under the hood runs the document processing code).
The client part depends on the document processing function being complete. So putting the client function in the document processing project creates a recursion where client needs client to be complete to complete.