chore: remove obsolete Azure DevOps CI configuration

CI has fully migrated to GitHub Actions (.github/workflows/). The old
Azure DevOps pipeline config is dead code.

- Delete ci/ directory (6 pipeline files)
- Delete root azure-pipelines.yml
- Drop ci/azure-pipelines.yml entry from repolint.json
  (.github/workflows/* already satisfies the OR-list)

Closes #790

Signed-off-by: Pranav dhiran <dhiranpranav72@gmail.com>

Author: Pranav-d33

azure-pipelines.yml

@@ -32,8 +32,7 @@
               ".circleci/config.yml", 
               "Jenkinsfile", 
               ".drone.yml",
-              ".github/workflows/*",
-              "ci/azure-pipelines.yml"
+              ".github/workflows/*"
             ]
           }
         ],