JIRA: Support Personal Access Tokens - backend

What does this MR do and why?

Per JIRA: Support Personal Access Tokens - backend (#364850 - closed), we are adding a new way of authorization for the Jira integration. From now, we are supporting PAT (personal access token), that doesn't require user/password combination.

Screenshots or screen recordings

New drop-down options:

Validation if Personal authentication token is chosen, and URL is a Jira Cloud instance (*.atlassian.net).

How to set up and validate locally

1. Checkout the branch
2. Go to integrations page of a single project
3. Try out the new field Authentication type
4. Validate it works without providing a username

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #364850 (closed)