Reverting usage of RE2 (WIP):

**Breaking changes**

The livechat v13 introduced a new library to handle regular expressions in forbidden words, to avoid
[ReDOS](https://en.wikipedia.org/wiki/ReDoS) attacks.
Unfortunately, this library was not able to install itself properly on some systems, and some admins were not able
to install the livechat plugin.

That's why we have disabled this library in v14, and introduce a new settings to enable regexp in forbidden words.
By default this settings is disabled, and your users won't be able to use regexp in their forbidden words.

The risk by enabling this feature is that a malicious user could cause a denial of service for the chat bot, by using a
special crafted regular expression in their channel options, and sending a special crafter message in one of their
rooms. If you trust your users (those who have rights to livestream), you can enable the settings. Otherwise it is not
recommanded. See the documentation for more informations.

**Minor changes and fixes**

* Channel's forbidden words: new "enable" column.
* New settings to enable regular expressions for channel forbidden words.
* "Channel advanced configuration" settings: removing the "experimental feature" label.

languages/zh-Hant.yml

@@ -99,7 +99,7 @@ livechat_configuration_channel_slow_mode_label: 限速模式
 livechat_configuration_channel_slow_mode_desc: "限速模式預設值：\n<ul>\n <li>0：停用限速模式</li>\n
   <li>任何正整數：使用者可以每 X 秒發送一條訊息（審核者不受限制）</li>\n</ul>\n"
 prosody_firewall_name: 名字
-prosody_firewall_file_enabled: 啟用
+enabled: 啟用
 livechat_configuration_channel_emojis_desc: "您可以為您的頻道組態自訂表情符號。\n這些表情符號將在表情符號選擇器中提供。\n\
   使用者也可以透過其短名稱來使用它們（例如透過編寫“:shortname:”）。\n"
 livechat_emojis_shortname: 簡稱