Add resource for configuring Jira Integration

[pascal-hofmann]

There currently does not seem a way to configure Jira integration via terraform.

For my use case I need the "Cloud" / "Basic auth" options.

In the UI this can be configured below Administration -> Xray Settings -> Integrations.

PS: I need this because we have automatically rotating credentials and updating them per hand is tedious and error prone.

[alexhung]

@pascal-hofmann There are REST APIs to manage integration for Xray but they are deprecated. This is why I haven't added support to the Xray provider. I don't know if there's plan to replace them with new REST APIs.

Like in #23, you can make feature request to the Xray team through JFrog customer support.