[FIX]Review the translation of the livechat

[renatobecker-zz]

@RocketChat/core
Closes #9848

The translations of the Livechat widget, admin and settings has been revised.
Some translations were missing both for English and Portuguese.

[sampaiodiego]

Translations seems to be still inconsistent:

FYI, running TAPi18n.getLanguage() on console gives me pt-BR

[renatobecker-zz]

Thanks @sampaiodiego for your review.
What's happening is that we have translation files in both the RocketChat folder and the Livechat folder.
So, when the LiveChat is open through the RocketChat port, the LiveChat translation files are not loaded.
I'm looking for the possibility to load the LiveChat translation files when the LiveChat is open through the RocketChat port.

[renatobecker-zz]

Hi @sampaiodiego !
As you can see, I made several changes in this PR.
I unified the translation files between LiveChat and RocketChat, so after finished this merger I removed all the translation files we had inside the i18n livechat folder.
Due to this I had to change the configuration of the Livechat TAPi18n, because the package was looking for i18n.json files but they don't exists any more.
So, I followed the package documentation, as you can see by clicking on this link:
https://github.com/TAPevents/tap-i18n#configuring-tap-i18n

I've tried some language translations, such as "pt-BR", "es", "it".. and it's working well.
The problem I've found is that when the browser language is "en", the translation is not working, so I would like you test this language to make sure it's not a problem in my test environment.

I'll be waiting for you review.