[various] Delete discontinued packages (flutter#9215)

Removes the following packages from the repository, as they have been discontinued:
- ios_platform_images
- css_colors
- palette_generator
- flutter_image
- flutter_adaptive_scaffold
- flutter_markdown

Fixes flutter/flutter#162960

Author: stuartmorgan-g

.github/dependabot.yml

@@ -33,9 +33,6 @@ updates:
       - /packages/extension_google_sign_in_as_googleapis_auth/example/android/app
       - /packages/file_selector/file_selector/example/android/app
       - /packages/file_selector/file_selector_android/example/android/app
-      - /packages/flutter_adaptive_scaffold/example/android/app
-      - /packages/flutter_image/example/android/app
-      - /packages/flutter_markdown/example/android/app
       - /packages/flutter_plugin_android_lifecycle/example/android/app
       - /packages/go_router/example/android/app
       - /packages/google_maps_flutter/google_maps_flutter/example/android/app
@@ -49,7 +46,6 @@ updates:
       - /packages/image_picker/image_picker_android/example/android/app
       - /packages/local_auth/local_auth_android/example/android/app
       - /packages/local_auth/local_auth/example/android/app
-      - /packages/palette_generator/example/android/app
       - /packages/path_provider/path_provider/example/android/app
       - /packages/path_provider/path_provider_android/example/android/app
       - /packages/pigeon/example/app/android/app

.github/labeler.yml

@@ -13,11 +13,6 @@
     - any-glob-to-any-file:
       - packages/cross_file/**/*
 
-'p: css_colors':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/css_colors/**/*
-
 'p: cupertino_icons':
   - changed-files:
     - any-glob-to-any-file:
@@ -38,26 +33,11 @@
     - any-glob-to-any-file:
       - packages/file_selector/**/*
 
-'p: flutter_adaptive_scaffold':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/flutter_adaptive_scaffold/**/*
-
-'p: flutter_image':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/flutter_image/**/*
-
 'p: flutter_lints':
   - changed-files:
     - any-glob-to-any-file:
       - packages/flutter_lints/**/*
 
-'p: flutter_markdown':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/flutter_markdown/**/*
-
 'p: flutter_migrate':
   - changed-files:
     - any-glob-to-any-file:
@@ -124,11 +104,6 @@
     - any-glob-to-any-file:
       - packages/interactive_media_ads/**/*
 
-'p: ios_platform_images':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/ios_platform_images/**/*
-
 'p: local_auth':
   - changed-files:
     - any-glob-to-any-file:
@@ -144,11 +119,6 @@
     - any-glob-to-any-file:
       - packages/multicast_dns/**/*
 
-'p: palette_generator':
-  - changed-files:
-    - any-glob-to-any-file:
-      - packages/palette_generator/**/*
-
 'p: path_parsing':
   - changed-files:
     - any-glob-to-any-file:

CODEOWNERS

@@ -7,13 +7,9 @@
 packages/animations/**                                   @hannah-hyj
 packages/camera/**                                       @bparrishMines
 packages/cross_file/**                                   @ditman
-packages/css_colors/**                                   @stuartmorgan-g
 packages/extension_google_sign_in_as_googleapis_auth/**  @ditman
 packages/file_selector/**                                @stuartmorgan-g
-packages/flutter_adaptive_scaffold/**                    @gspencergoog
-packages/flutter_image/**                                @stuartmorgan-g
 packages/flutter_lints/**                                @chunhtai
-packages/flutter_markdown/**                             @domesticmouse
 packages/flutter_migrate/**                              @stuartmorgan-g
 packages/flutter_template_images/**                      @stuartmorgan-g
 packages/go_router/**                                    @chunhtai
@@ -28,7 +24,6 @@ packages/in_app_purchase/**                              @bparrishMines
 packages/local_auth/**                                   @stuartmorgan-g
 packages/metrics_center/**                               @christopherfujino
 packages/multicast_dns/**                                @vashworth
-packages/palette_generator/**                            @gspencergoog
 packages/path_provider/**                                @stuartmorgan-g
 packages/pigeon/**                                       @tarrinneal
 packages/platform/**                                     @stuartmorgan-g
@@ -97,7 +92,6 @@ packages/google_sign_in/google_sign_in_ios/**            @LongCatIsLooong @cbrac
 packages/image_picker/image_picker_ios/**                @vashworth @louisehsu
 packages/image_picker/image_picker_macos/**              @vashworth @louisehsu
 packages/in_app_purchase/in_app_purchase_storekit/**     @louisehsu @LongCatIsLooong
-packages/ios_platform_images/**                          @vashworth
 packages/local_auth/local_auth_darwin/**                 @cbracken @vashworth
 packages/path_provider/path_provider_foundation/**       @cbracken @vashworth
 packages/pigeon/**/ios/**/*                              @louisehsu @hellohuanlin