Feature(integrate zentao): part of Controllers

part of Issue: #338178 (closed)

base on MR: !68454 (closed)

MR to review: icbd/gitlab!7 (closed)

How to setup and validate locally

1. Enable the zentao_issues_integration feature flag
2. Create a project
3. Settings(project level) => Integrations => ZenTao
4. Fill in the ZenTao demo account
5. Click Test settings and Save changes
6. Click ZenTao issues on the left menu

ZenTao demo account

Zentao Web URL: https://jihudemo.zentao.net
Zentao API token: a70fe861f1e60a3bfd857133798f2f1f
Zentao Product ID: 3

Video demo:

zentao-integration-video-demo

Views Look like

Issue List (left is zentao page, right is gitlab page)

Filter and Search

status tab and pagination

Issue detail page