Proposal: add API based end-to-end (aka e2e) testing

[LinuxSuRen]

hi go-admin team, I'm the author of api-testing which is an API testing tool. It seems that no e2e testing in this project. I'd be happy to implement it if you belive it's worth.

In order to let you have a quick kowning about it. Please see also the user's of api-testing.

[wenjianzhang]

If you can, we'd really appreciate it!

[LinuxSuRen]

Okay, I'm going to give it a try.