Awx: notification backends allow ssrf and credential leakage

A server-side request forgery (SSRF) vulnerability was found in multiple AWX notification backends. The webhook, Mattermost, Rocket.Chat, and Grafana notification backends use notification template URLs as direct HTTP request targets without validating the target address against private, loopback, or reserved IP ranges. An organization notification administrator can create notification templates pointing to internal or loopback addresses, causing the AWX control node to issue HTTP requests to services that are not externally accessible. Additionally, the webhook notification backend follows HTTP redirects and resends configured Basic Authentication credentials to redirect targets regardless of host change, allowing an attacker to exfiltrate notification credentials by redirecting to an attacker-controlled host. The Grafana backend sends its API key in the Authorization header to the configured target URL.