feat(kubernetes): Add styling based on current context (#4550)

* feat(kubernetes): Add styling based on current context

Add an ability to customize the configuration of the kubernetes module style, based on the current context.

A new variable is added to the config section, called environments, which is a list of possible customizations. Each such customization is an object with a context_pattern regex, which matches context name, and an optional style and icon that will override the global configuration, if the currently used context matched the context_pattern.

Based on multiple attempts to add per-context styling and symbols to the kubernetes module.

- https://github.com/starship/starship/pull/1568 by @lht https://github.com/lht -> base
- https://github.com/starship/starship/pull/614 by @nomaed https://github.com/nomaed -> naming, symbol, some tests

Rebased and combined by @jankatins

Contains the following squasched commits

- Rename to contexts and move aliases into contexts
- Move deprecated functions to a submodule
- Cleanup: ignore None-valued KubeCtxComponents
- Add regex func + clean up matching-context search
- Placate paper clip

Closes: https://github.com/starship/starship/issues/570

Co-authored-by: =?UTF-8?q?Boris=20Aranovic=CC=8C?= <nomaed@gmail.com>
Co-authored-by: Jan Katins <jasc@gmx.net>
Co-authored-by: Kevin Song <chips@ksong.dev>

* refactor(kubernetes): Remove options and use clearer names

* test(kubernetes): Handle duplicated contexts right

* refactor(kubernetes): Cleaner user matching

* fix(kubernetes): Only show warning in case of problems

* feat(kubernetes): Add back alias replacements

* refactor(kubernetes): Cleanup rust usage

---------

Co-authored-by: Haitao Li <lihaitao@gmail.com>
Co-authored-by: =?UTF-8?q?Boris=20Aranovic=CC=8C?= <nomaed@gmail.com>
Co-authored-by: Kevin Song <chips@ksong.dev>
Co-authored-by: David Knaack <davidkna@users.noreply.github.com>

.github/config-schema.json

@@ -906,6 +906,7 @@
     "kubernetes": {
       "default": {
         "context_aliases": {},
+        "contexts": [],
         "detect_extensions": [],
         "detect_files": [],
         "detect_folders": [],
@@ -4013,6 +4014,58 @@
           "items": {
             "type": "string"
           }
+        },
+        "contexts": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/KubernetesContextConfig"
+          }
+        }
+      },
+      "additionalProperties": false
+    },
+    "KubernetesContextConfig": {
+      "type": "object",
+      "properties": {
+        "context_pattern": {
+          "default": "",
+          "type": "string"
+        },
+        "user_pattern": {
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "symbol": {
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "style": {
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "context_alias": {
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "user_alias": {
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ]
         }
       },
       "additionalProperties": false