feat(k8s): Add folder detection to the k8s module. (#4157)

Have added configuration options to the k8s module to allow activating
the module only in directories that contains certain files or folders.
To ensure this is backwards compatible and because there are not really
any standard files or folders for Kubernetes I have set the defaults to
empty and will activate the module for all directories.

.github/config-schema.json

@@ -767,6 +767,9 @@
     "kubernetes": {
       "default": {
         "context_aliases": {},
+        "detect_extensions": [],
+        "detect_files": [],
+        "detect_folders": [],
         "disabled": true,
         "format": "[$symbol$context( \\($namespace\\))]($style) in ",
         "style": "cyan bold",
@@ -3323,6 +3326,27 @@
           "additionalProperties": {
             "type": "string"
           }
+        },
+        "detect_extensions": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_files": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_folders": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
         }
       }
     },