Adds `SAPODataConnector`, `SAPODataEntity`, and `SAPIngestor` for ingesting master and transactional data from SAP OData services, mainly things like Business Partners and Sales Orders.
Tested around S/4HANA Cloud, SuccessFactors, and on-prem NetWeaver Gateway style OData endpoints.
Main pieces included:
* OAuth2 client credentials and Basic auth support. Both go through the existing `ssrf.py` checks, including the OAuth token request.
* Small EDMX parser used by `discover_service()` so we don't need to pull in `pyodata`.
* Server-side pagination support for both OData versions:
* v2: `__next`, including plain string and `__deferred` formats
* v4: `@odata.nextLink`
* Keeps the service path in the base URL correctly whether the URL has a trailing slash or not. This is normalized in `SAPIngestor.__init__`.
* Adds an `ingest-sap` extra with just `requests`, so there is no SAP/proprietary SDK dependency.
This is meant to be a fairly small first version of the connector without adding a lot of SAP-specific dependencies.
Closes#1228
Kevin Zhang
100e95a098