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/zh/common.json

@@ -325,13 +325,13 @@
     "view_contact": "查看联系人",
     "message_details": "邮件详情",
     "more_reply_options": "更多回复选项",
-    "set_color": "设置颜色标签",
+    "set_tag": "设置颜色标签",
     "tag": "标签",
     "more_actions": "更多操作",
     "previous": "上一封",
     "next": "下一封",
     "move_to": "移动到…",
-    "remove_color": "删除标签",
+    "remove_tag": "删除标签",
     "more_count": "+{count} 更多",
     "characters_count": "{count} 个字符",
     "quick_reply_placeholder": "快速回复...",
@@ -400,17 +400,6 @@
       "message_id": "消息 ID",
       "list_info": "邮件列表信息"
     },
-    "color_tag": {
-      "title": "颜色标签",
-      "red": "红色",
-      "orange": "橙色",
-      "yellow": "黄色",
-      "green": "绿色",
-      "blue": "蓝色",
-      "purple": "紫色",
-      "pink": "粉色",
-      "none": "无"
-    },
     "tooltips": {
       "reply": "回复 (r)",
       "reply_all": "全部回复 (a)",
@@ -2033,8 +2022,7 @@
     "delete": "删除",
     "mark_as_spam": "举报垃圾邮件",
     "not_spam": "不是垃圾邮件",
-    "color_tag": "标签",
-    "remove_color": "删除标签",
+    "tag": "标签",
     "items_selected": "已选择 {count} 封邮件",
     "edit_draft": "编辑草稿",
     "cancel_scheduled_send": "取消发送",