Add support for new custom properties for orgs APIs

[stevehipwell]

GitHub announced support for organization custom properties. This will also require support adding to enterprise rules as the selector can now use organization properties.

• Enterprise REST API to configure custom properties
• Organization REST API to set custom properties

[gmlewis]

This would be a great PR for any new contributor to this repo or a new Go developer.
All contributions are greatly appreciated!

Feel free to volunteer for any issue and the issue can be assigned to you so that others don't attempt to duplicate the work.
Also feel free to perform a code review on any PR that has the label "NeedsReview" - we appreciate those contributions too!
We have a REVIEWERS file that you could add your username to if you are willing to be contacted when reviews are needed.

Please check out our CONTRIBUTING.md guide to get started. (In particular, please remember to go generate ./... and don't use force-push to your PRs.)

Thank you!

[Not-Dhananjay-Mishra]

I’d love to work on this!
I just have a couple of questions:

• Should I create two new files one for the Enterprise REST API to configure custom properties and another for the Organization REST API or should I add the implementation to the existing files? If new files are preferred, could you please suggest appropriate names for them?
• Do I also need to make any changes in enterprise_rules.go?

[stevehipwell]

@Not-Dhananjay-Mishra thank you, the issue is yours.

Should I create two new files one for the Enterprise REST API to configure custom properties and another for the Organization REST API or should I add the implementation to the existing files? If new files are preferred, could you please suggest appropriate names for them?

I think that would make sense to have two new files, but naming is hard especially when GitHub features are involved.

Do I also need to make any changes in enterprise_rules.go?

Yes, enterprise rules can now target orgs by property.

/assign @Not-Dhananjay-Mishra

[Not-Dhananjay-Mishra]

@gmlewis I am getting this error while runing go generate ./...
could not find operation "GET /enterprises/{enterprise}/org-properties/schema" in openapi_operations.yaml
could not find operation "PATCH /enterprises/{enterprise}/org-properties/schema" in openapi_operations.yaml
could not find operation "GET /enterprises/{enterprise}/org-properties/schema/{custom_property_name}" in openapi_operations.yaml
could not find operation "PUT /enterprises/{enterprise}/org-properties/schema/{custom_property_name}" in openapi_operations.yaml
could not find operation "DELETE /enterprises/{enterprise}/org-properties/schema/{custom_property_name}" in openapi_operations.yaml
could not find operation "GET /enterprises/{enterprise}/org-properties/values" in openapi_operations.yaml
could not find operation "PATCH /enterprises/{enterprise}/org-properties/values" in openapi_operations.yaml
could not find operation "GET /organizations/{org}/org-properties/values" in openapi_operations.yaml
could not find operation "PATCH /organizations/{org}/org-properties/values" in openapi_operations.yaml

[gmlewis]

@Not-Dhananjay-Mishra - it looks like I need to update the openapi definitions.
I'll work on that and report back.

[gmlewis]

@Not-Dhananjay-Mishra - please merge the latest version of master into your branch and see if that solves the problems you were seeing.

[Not-Dhananjay-Mishra]

@gmlewis Thanks a lot