Simplify SSE tutorials and refer to KES docs (#1136)

This PR simplifies the management of KMS integrations by removing the
detailed documentation and linking out to the KES docs site instead.

There should be no mention of any specific KMS target.
Each OS/platform should have references to the correct paths, OS, and
the like.

This completes work started on the KES docs side in
https://github.com/minio/kes-docs/pull/48.

Staged:

-
[Linux](http://192.241.195.202:9000/staging/ssekms/linux/operations/server-side-encryption/configure-minio-kes.html)
-
[Windows](http://192.241.195.202:9000/staging/ssekms/windows/operations/server-side-encryption/configure-minio-kes.html)
-
[Kubernetes](http://192.241.195.202:9000/staging/ssekms/k8s/operations/server-side-encryption/configure-minio-kes.html)
-
[Containers](http://192.241.195.202:9000/staging/ssekms/container/operations/server-side-encryption/configure-minio-kes.html)
-
[MacOS](http://192.241.195.202:9000/staging/ssekms/macos/operations/server-side-encryption/configure-minio-kes.html)

source/reference/minio-server/settings/kes.rst

@@ -32,7 +32,12 @@ Refer to your operating system's documentation for how to define an environment
    The private key associated to the the :envvar:`MINIO_KMS_KES_CERT_FILE` x.509 certificate to use when authenticating to the KES server. 
    The KES server requires clients to present their certificate for performing mutual TLS (mTLS).
 
-   See the :minio-git:`KES wiki <kes/wiki/Configuration#policy-configuration>` for more complete documentation on KES access control.
+   See the :minio-git:`KES wiki <kes/wiki/Configuration#policy-configuration>` for more complete documentation on KES access control.'
+
+.. envvar:: MINIO_KMS_KES_CAPATH
+
+   Allows validation of the KES Server Certificate for a Self-Signed or Third-Party :abbr:`CA <Certificate Authority>`.
+   Specify the path to the location of the :abbr:`CA <Certificate Authority>` certificate for your KES deployment.
 
 .. envvar:: MINIO_KMS_KES_CERT_FILE