[feat] categories: add icons for remaining category tabs (#6759)

Icons are provided for the main categories known to us.

The distinction between CATEGORY_GROUPS and CATEGORY_NAMES is abandoned in favor
of the latter.

HINT: we need single-color icons; transparent background and the color must be
`currentColor` so that the icons can be used in light/dark themes.

The following SVGs from the ionicons had to be revised (use ``currentColor``).

- client/simple/src/svg/ionicons/logo-rss.svg
- client/simple/src/svg/ionicons/radio-outline.svg
- client/simple/src/svg/ionicons/color-palette-outline.svg

For the following categories, I did not find any usable icons in Ionicons; new
SVGs were created for these categories.

- onions: client/simple/src/svg/ionicons/tor-browser.svg
- lyrics: client/simple/src/svg/ionicons/song-lyric-music.svg [1]
- packages: client/simple/src/svg/ionicons/package_2.svg [1]

[1] Based on Google's Material icons: https://fonts.google.com/icons

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/templates/simple/categories.html

@@ -1,20 +1,30 @@
 {% from 'simple/icons.html' import icon_big %}
 {%- set category_icons = {
-    'apps': 'appstore',
-    'dictionaries': 'book',
-    'files': 'file-tray-full',
-    'general': 'search',
-    'images': 'image',
-    'it': 'layers',
-    'map': 'location',
-    'music': 'musical-notes',
-    'news': 'newspaper',
-    'radio': 'radio',
-    'science': 'school',
-    'social media': 'people',
-    'TV': 'tv',
-    'videos': 'play',
-}  -%}
+    "apps": "appstore",
+    "blogs": "rss",
+    "dictionaries": "book",
+    "files": "file-tray-full",
+    "general": "search",
+    "icons": "palette",
+    "images": "image",
+    "it": "layers",
+    "lyrics": "lyrics",
+    "map": "location",
+    "movies": "videocam",
+    "music": "musical-notes",
+    "news": "newspaper",
+    "onions": "tor",
+    "packages": "package",
+    "radio": "radio",
+    "repos": "file-tray-stacked",
+    "science": "school",
+    "social media": "people",
+    "stock images": "camera",
+    "translate": "language",
+    "TV": "tv",
+    "videos": "play",
+    "weather": "rainy",
+  }  -%}
 <div id="categories" class="search_categories">{{- '' -}}
     <div id="categories_container">
         {%- if not search_on_category_select or not display_tooltip -%}