net/p5-Net-Mosso-CloudFiles: Mark DEPRECATED

• Switch to DISTVERSION while I am here
• Set EXPIRATION_DATE 2026-10-23
• Rackspace retired the legacy auth.api.rackspacecloud.com endpoint (Cloud Files' pre-OpenStack auth) on 2025-05-19
• This module's simple user/key constructor uses that legacy scheme and was never updated to the current Keystone-based identity API, making it non-functional against current Rackspace Cloud Files

(cherry picked from commit 06b9ff0d0892d6ceb0b02f28289512913993f4f8)