Merge branch '214318-jira-issues-import-mvc-docs' into 'master'

Add documetation on Jira issues import MVC

See merge request gitlab-org/gitlab!29480

doc/user/project/import/index.md

@@ -15,6 +15,7 @@
 1. [By uploading a manifest file (AOSP)](manifest.md)
 1. [From Gemnasium](gemnasium.md)
 1. [From Phabricator](phabricator.md)
+1. [From Jira (issues only)](jira.md)
 
 In addition to the specific migration documentation above, you can import any
 Git repository via HTTP from the New Project page. Be aware that if the

doc/user/project/import/jira.md

+# Import your Jira project issues GitLab
+
+Using the importer, you can import your Jira issues to GitLab.com or to
+your self-managed GitLab instance.
+
+## Overview
+
+Jira issues import is a MVC feature introduced in 12.10 as a project level feature, meaning that issues from multiple
+Jira projects can be imported into a GitLab project. MVC version imports issue title and descriptio as well as some
+other issue metadata as a section in the issue description.
+
+## Prerequisites
+
+### Permissions
+
+In order to be able to import issues from a Jira project users need to have read access on Jira issues as well as
+maintainer or owner role in GitLab project that you wish to import into or site admin role.
+
+### Jira Integration
+
+Jira import feature makes use of an existing [Jira integration](../integrations/jira.md) feature within GitLab. Please
+esure you have the integration setup before trying to import Jira issues.
+
+## How to import
+
+Jira issues import is being integrated into GitLab issues feature and can be triggered by clicking the `Import Issues` button
+and selecting `Import from Jira` option.
+![Import issues from Jira button](img/jira/import_issues_from_jira_button_v12_10.png)
+
+Selecting the `Import from Jira` will bring you to the following form.
+![Import issues from Jira form](img/jira/import_issues_from_jira_form_v12_10.png)
+
+At this point if you have had the [Jira integration](../integrations/jira.md) setup, you should be able to see the Jira
+projects that you have access to in the dropdown and select the Jira project that you wish to import issues from.
+![Import issues from Jira form](img/jira/import_issues_from_jira_projects_v12_10.png)
+
+Next you click `Import Issues` and you should be presented with a confirmation that import has started. While import is
+running in the background you can navigate away from import status page to issues page and should be able to see new issues
+poping up in the issues list.
+
+NOTE: **Note:**
+While Jira issues import happens in real time, it is done in an asynchroneous background job, which may result in delays
+based on import queues load, system load or other factors. Importing large projects may take several minutes depending
+on the size of the import, you can check the status by navigating to the Jira import page
+![Import issues from Jira button](img/jira/import_issues_from_jira_button_v12_10.png)