GraphQL endpoint for Jira users import

What does this MR do?

It adds a graphQL endpoint for importing users from Jira. The users are trying to be matched by email and displayName and respective gitlab ids are assigned if matching is successful.

Examples

Request

mutation {
  jiraImportUsers(input: {startAt: 1, projectPath: "flightjs/flight"}) {
    errors
    jiraUsers {
      jiraAccountId
      jiraDisplayName
      jiraEmail
      gitlabId
    }
  }
}

Response

{
  "data": {
    "jiraImportUsers": {
      "errors": [],
      "jiraUsers": [
        {
          "jiraAccountId": "557058:214cdd6a-ff93-4d8b-838b-62dfcf1a2a71",
          "jiraDisplayName": "Jarka K.",
          "jiraEmail": null,
          "gitlabId": null
        }
       ]
    }
  }
}

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.

Issue: #216145 (closed)