Merge PKI & KMS docs (#4325)

* Merge PKI & KMS docs

* Update worker-configuration.mdx

remove deprecated kms flag

* docs: Fix TOC

* docs: Create redirects

* docs: Fix some broken links

* modify overview page for post 0.15 changes

* Modify data-encryption docs for post 0.15

* modify configure-workers page for post 0.15

---------

Co-authored-by: Dan Heath <76443935+Dan-Heath@users.noreply.github.com>

website/data/docs-nav-data.json

@@ -375,12 +375,8 @@
             "path": "configuration/worker"
           },
           {
-            "title": "PKI workers",
-            "path": "configuration/worker/pki-worker"
-          },
-          {
-            "title": "KMS workers",
-            "path": "configuration/worker/kms-worker"
+            "title": "Configuration",
+            "path": "configuration/worker/worker-configuration"
           }
         ]
       },