Add product-specific NIST 800-53 control files

Add NIST 800-53 Revision 5 control files for rhel8, rhel9, and rhel10.
Each product has 21 family files containing rule mappings derived from
CIS benchmark to NIST 800-53 control mappings.

Product control files (used in builds):
  - products/rhel8/controls/nist_800_53.yml + 21 family files
  - products/rhel9/controls/nist_800_53.yml + 21 family files
  - products/rhel10/controls/nist_800_53.yml + 21 family files

Reference files (auto-generated for comparison):
  - shared/references/controls/nist_800_53_cis_reference_rhel8.yml + 21 family files
  - shared/references/controls/nist_800_53_cis_reference_rhel9.yml + 21 family files
  - shared/references/controls/nist_800_53_cis_reference_rhel10.yml + 21 family files

Author: ggbecker

products/rhel10/controls/nist_800_53.yml

@@ -0,0 +1,23 @@
+# Product-Specific NIST 800-53 Control File (RHEL10)
+#
+# This file contains product-specific metadata for RHEL10.
+# Control families are in nist_800_53/ subdirectory (21 family files).
+#
+# Generated from CIS benchmark mappings to NIST 800-53 controls.
+# Rules are filtered to only those available in RHEL10.
+# NO Jinja2 guards - rules are product-specific.
+#
+# OSCAL metadata (description, parameters, guidance, related_controls) is NOT
+# included in control files. Retrieve from OSCAL catalog when needed.
+#
+policy: NIST 800-53 Revision 5
+title: NIST Special Publication 800-53 Revision 5
+id: nist_800_53
+version: Revision 5
+source: https://csrc.nist.gov/publications/detail/sp/800-53/rev-5/final
+product: rhel10
+controls_dir: nist_800_53
+levels:
+- id: low
+- id: moderate
+- id: high