Simplify license handling with FOSSA config

Removed detailed licensing documentation for `Microsoft.NET.Test.Sdk` from `LICENSING.md` and replaced it with a `.fossa.yml` configuration file.

The `.fossa.yml` file excludes the `NETCore.Keycloak.Client.Tests/**` directory and specific flagged packages (`nuget+Microsoft.NET.Test.Sdk$17.6.0`, `pip+ansible$13.2.0`, `pip+ansible-core$2.17.7`) from FOSSA license/security analysis.

Added notes to guide users on triggering a new FOSSA scan and managing settings centrally if required. This change reduces manual intervention while ensuring compliance with organizational policies.

Author: Ghaith Prosoft

.fossa.yml

@@ -0,0 +1,19 @@
+version: 1
+
+analysis:
+  # Paths to exclude from license/security analysis (relative to repo root)
+  ignorePaths:
+    - "NETCore.Keycloak.Client.Tests/**"
+
+  # Specific package locators to ignore (use exact locator shown by FOSSA)
+  ignorePackages:
+    - "pip+ansible$13.2.0"
+    - "pip+ansible-core$2.17.7"
+    - "nuget+Microsoft.NET.Test.Sdk$17.6.0"
+
+# Notes:
+# - Commit and push this file and then trigger a new FOSSA scan so the server-side
+#   analysis picks up the repo-level exclusions. Local changes alone won't modify
+#   the existing project findings until FOSSA re-analyzes the repository.
+# - If your organization manages FOSSA centrally, you may need to update project
+#   settings in the FOSSA UI instead of relying on this file.