Pygyver

* `OmetriaExecutor` API handler added - `from pygyver.etl.ometria import OmetriaExecutor`
* added new slicing function to `toolkit`

- Change `execute_schedule` behaviour to only await completion of running schedules when specified.
- This was required when it was not possible to run ADD schedules at the same time

ZendeskDownloader` changes:
- update to allow for incremental loads via a start_date param.
- add per_page param to enable the declaration of the number of records per response page. This may help if the default 1000 records is too large for processing.
- add pagination param to define if the endpoint has pagination.
- improve error handing.
- improve docstring documentation.
- improve logging.

- cryptography package bumped to v3.2
- improve logging on Zendesk `api_call` function to make response codes more visible
- update logic for `keep_running` function

ZendeskDownloader` class added to handle requests to the Zendesk API

Updated read_sql() to remove project names during the dry-run tests