Zoura oAuth support

[avida]

Resolves #7112

Zuora supports only oAuth client_credentials grant type. That means we have nothing to do on backend, only inject client_id/client_secret parameters wnen doing check_connection/read operations.

But still there is Authorization button on UI that doing nothing, I can see couple of solutions on this:

• Do not show Authorization button if there is oauthFlowOutputParameters is empty;
• Use Authorization button to check if provided credentials are correct. In this cause we need
  a) mechanism to pass oAuth input parameters (as for OAuth Flow: new authSpecifications supporting field references from connector config as dependency #6971 issues) because Zuora authorization endpoint is dependant on "tenant_endpoint" parameter
  b) Additional UI flow for those cases.

[avida]

/test connector=connectors/source-zuora

🕑 connectors/source-zuora https://github.com/airbytehq/airbyte/actions/runs/1385061140
✅ connectors/source-zuora https://github.com/airbytehq/airbyte/actions/runs/1385061140
Python tests coverage:

	 ---------- coverage: platform linux, python 3.8.10-final-0 -----------
	 Name                                                 Stmts   Miss  Cover
	 ------------------------------------------------------------------------
	 source_acceptance_test/__init__.py                       2      0   100%
	 source_acceptance_test/base.py                          10      4    60%
	 source_acceptance_test/config.py                        74      8    89%
	 source_acceptance_test/conftest.py                     108    108     0%
	 source_acceptance_test/plugin.py                        47     47     0%
	 source_acceptance_test/tests/__init__.py                 4      0   100%
	 source_acceptance_test/tests/test_core.py              200     94    53%
	 source_acceptance_test/tests/test_full_refresh.py       18     11    39%
	 source_acceptance_test/tests/test_incremental.py        69     38    45%
	 source_acceptance_test/utils/__init__.py                 6      0   100%
	 source_acceptance_test/utils/asserts.py                 37      2    95%
	 source_acceptance_test/utils/common.py                  41     24    41%
	 source_acceptance_test/utils/compare.py                 47     20    57%
	 source_acceptance_test/utils/connector_runner.py        82     49    40%
	 source_acceptance_test/utils/json_schema_helper.py     115     14    88%
	 ------------------------------------------------------------------------
	 TOTAL                                                  860    419    51%
	 ---------- coverage: platform linux, python 3.8.10-final-0 -----------
	 Name                                     Stmts   Miss  Cover
	 ------------------------------------------------------------
	 source_zuora/__init__.py                     2      0   100%
	 source_zuora/source.py                     208     52    75%
	 source_zuora/zuora_auth.py                  19      0   100%
	 source_zuora/zuora_endpoint.py               4      0   100%
	 source_zuora/zuora_errors.py                30     13    57%
	 source_zuora/zuora_excluded_streams.py       2      0   100%
	 ------------------------------------------------------------
	 TOTAL                                      265     65    75%
	 ---------- coverage: platform linux, python 3.8.10-final-0 -----------
	 Name                                     Stmts   Miss  Cover
	 ------------------------------------------------------------
	 source_zuora/__init__.py                     2      2     0%
	 Name                                     Stmts   Miss  Cover/actions-runner/_work/airbyte/airbyte/airbyte-integrations/connectors/source-zuora/.venv/lib/python3.8/site-packages/coverage/control.py:761: CoverageWarning: No data was collected. (no-data-collected)
	 source_zuora/source.py                     208    208     0%
	 source_zuora/zuora_auth.py                  19     19     0%
	 source_zuora/zuora_endpoint.py               4      4     0%
	 source_zuora/zuora_errors.py                30     30     0%
	 source_zuora/zuora_excluded_streams.py       2      2     0%
	 ------------------------------------------------------------
	 TOTAL                                      265    265     0%