Process user mapping form and store the mapping

• Jira users that were not matched will be ignored
• Store the mapping in the temp structure
  • for the first integration, we will only store the mapping temporarily in Redis, key-value: jira-user-key=>user id (the mapping will be removed after another import for the Jira project - Gitlab project pair has started or after 1 week period), in the future we might consider storing the mapping permanently - to be discussed