chore: add Ansible project scaffolding

Add ansible.cfg (roles_path, inventory, become, fact caching),
requirements.yml placeholder for future collections, .gitignore for
Ansible artifacts, and .ansible-lint config for code quality.

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requirements.yml

@@ -0,0 +1,7 @@
+# requirements.yml
+#
+# External Ansible collections this project depends on. Currently empty —
+# the roles in ./roles/ are self-contained and use only ansible.builtin.*
+# modules. Add collections here as the STIG/CMMC/FedRAMP/ITAR hardening
+# library grows (e.g. ansible.posix, community.crypto, community.general).
+collections: []