feat: add optional owner param to syncer methods

[elierotenberg]

Previous implementation always used this.orgName for the required owner field, however the expected owner can be a user name, and not an org name.
For example, the Casdoor web app always sets the owner to "admin".
This in turns make it impossible to retrieve syncers created through the web app using the SDK.

This addition fixes this issue by adding an optional owner parameter to the syncer methods.

[casbin-bot]

@tangyang9464 @imp2002 please review

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[hsluoyz]

@elierotenberg see the Go SDK: https://github.com/casdoor/casdoor-go-sdk/blob/master/casdoorsdk/syncer_test.go

See the syncer test case and it passes. The CURD works.

[elierotenberg]

The Go SDK has the exact same problem.
I will also create a PR there.

[hsluoyz]

@elierotenberg what's wrong here? Do you think the test case is wrong?

[elierotenberg]

The test case isn't wrong, and there is not bug per se, rather that it is not currently possible to query the endpoint with an owner value that is not the current orgName.
There is nothing in the back-end implementation imposing that the owner is the current orgName, as illustrated by the Casdoor web app.

This is a debatable choice on the web app side as well however, the existence of a separate field organization in the Syncer model indicates that these are 2 separate, possibly distinct values.

The use case I am facing is:

1. I create a syncer through the web UI (owner is admin, organization is built-in),
2. I fetch the syncers through the SDKs (this.config.orgName is built-in) and an empty array is returned.

The proposed change is fully backwards compatible and simply allows the caller to explicitly specify the owner, defaulting to the previous behavior (this.config.orgName).

[hsluoyz]

@elierotenberg you should modify orgName, we don't add new parameter. Initialize new client with different orgName