feat: improve visualization of tags

Previously tags where very much focused on color coding email and less about
adding additional information. They were also visualized in different ways in
different locations.

This commit gets rid of all "Color-coding" references, aligns visualization of
the tags across the whole project and tries to improve user experience of using
tags in general.

A search box is shown in the tagging control so the user can quickly search for
a tag if they have a huge (more than 10) amount of tags.

locales/cs/common.json

@@ -325,13 +325,13 @@
     "view_contact": "Zobrazit kontakt",
     "message_details": "Podrobnosti zprávy",
     "more_reply_options": "Další možnosti odpovědi",
-    "set_color": "Nastavit štítek",
+    "set_tag": "Nastavit štítek",
     "tag": "Štítek",
     "more_actions": "Další akce",
     "previous": "Předchozí",
     "next": "Další",
     "move_to": "Přesunout do...",
-    "remove_color": "Odebrat štítek",
+    "remove_tag": "Odebrat štítek",
     "more_count": "+{count} dalších",
     "characters_count": "{count} znaků",
     "quick_reply_placeholder": "Napsat rychlou odpověď...",
@@ -400,17 +400,6 @@
       "message_id": "ID zprávy",
       "list_info": "Informace o konferenci"
     },
-    "color_tag": {
-      "title": "Barevný štítek",
-      "red": "Červený",
-      "orange": "Oranžový",
-      "yellow": "Žlutý",
-      "green": "Zelený",
-      "blue": "Modrý",
-      "purple": "Fialový",
-      "pink": "Růžový",
-      "none": "Žádný"
-    },
     "tooltips": {
       "reply": "Odpovědět (r)",
       "reply_all": "Odpovědět všem (a)",
@@ -2033,8 +2022,7 @@
     "delete": "Odstranit",
     "mark_as_spam": "Nahlásit spam",
     "not_spam": "Není spam",
-    "color_tag": "Štítek",
-    "remove_color": "Odebrat štítek",
+    "tag": "Štítek",
     "items_selected": "{count} vybraných zpráv",
     "edit_draft": "Upravit koncept",
     "cancel_scheduled_send": "Zrušit odeslání",