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/de/common.json

@@ -325,11 +325,11 @@
     "view_contact": "Kontakt anzeigen",
     "message_details": "Nachrichtendetails",
     "more_reply_options": "Weitere Antwortoptionen",
-    "set_color": "Label setzen",
+    "set_tag": "Label setzen",
     "tag": "Label",
     "more_actions": "Weitere Aktionen",
     "move_to": "Verschieben nach...",
-    "remove_color": "Label entfernen",
+    "remove_tag": "Label entfernen",
     "more_count": "+{count} weitere",
     "characters_count": "{count} Zeichen",
     "quick_reply_placeholder": "Eine kurze Antwort schreiben...",
@@ -398,17 +398,6 @@
       "message_id": "Nachrichten-ID",
       "list_info": "Listeninformationen"
     },
-    "color_tag": {
-      "title": "Farb-Tag",
-      "red": "Rot",
-      "orange": "Orange",
-      "yellow": "Gelb",
-      "green": "Grün",
-      "blue": "Blau",
-      "purple": "Violett",
-      "pink": "Rosa",
-      "none": "Keine"
-    },
     "tooltips": {
       "reply": "Antworten",
       "reply_all": "Allen antworten (a)",
@@ -2033,8 +2022,7 @@
     "delete": "Löschen",
     "mark_as_spam": "Spam melden",
     "not_spam": "Kein Spam",
-    "color_tag": "Label",
-    "remove_color": "Label entfernen",
+    "tag": "Label",
     "items_selected": "{count} E-Mails ausgewählt",
     "edit_draft": "Entwurf bearbeiten",
     "cancel_scheduled_send": "Senden abbrechen",