DOCSP-12574: update use cases nav item n ame (#677)

* DOCSP-12574: update use cases nav item name

Author: Chris Cho

source/index.txt

@@ -27,4 +27,4 @@ MongoDB Drivers
    Swift Driver </swift>
    Rust Driver </rust>
    About Compatibility Tables <about-compatibility>
-   /use-cases
+   Security </security>

source/security.txt

@@ -0,0 +1,15 @@
+========
+Security
+========
+
+.. default-domain:: mongodb
+
+
+- :doc:`/security/client-side-field-level-encryption-guide`
+- :doc:`/security/client-side-field-level-encryption-local-key-to-kms`
+
+.. toctree::
+   :titlesonly:
+
+   /security/client-side-field-level-encryption-guide.txt
+   /security/client-side-field-level-encryption-local-key-to-kms.txt

source/use-cases/client-side-field-level-encryption-guide.txt renamed to source/security/client-side-field-level-encryption-guide.txt

@@ -288,7 +288,7 @@ the same MongoDB replica set as the encrypted data.
 
    To learn how to use a KMS in your CSFLE implementation, read the
    :doc:`Client-Side Field Level Encryption: Use a KMS to Store the Master Key
-   </use-cases/client-side-field-level-encryption-local-key-to-kms/>`
+   </security/client-side-field-level-encryption-local-key-to-kms/>`
    guide.
 
 To begin development, MedcoMD engineers generate a master key and save it
@@ -1052,7 +1052,7 @@ secure storage location such as a Key Management System (KMS).
 
 For more information on securing your master key, see our :doc:`step-by-step
 guide to integrating with Amazon KMS
-</use-cases/client-side-field-level-encryption-local-key-to-kms/>`.
+</security/client-side-field-level-encryption-local-key-to-kms/>`.
 
 Further Reading
 ~~~~~~~~~~~~~~~

source/use-cases/client-side-field-level-encryption-local-key-to-kms.txt renamed to source/security/client-side-field-level-encryption-local-key-to-kms.txt

@@ -25,7 +25,7 @@ AWS KMS.
 
 For a detailed walkthrough on developing and configuring a CSFLE client
 with an example use case, see our `CSFLE guide
-</use-cases/client-side-field-level-encryption-guide>`_.
+</security/client-side-field-level-encryption-guide>`_.
 
 Reasons to Use a KMS
 --------------------