FR: Errors returned in several languages

### Environment

* Operating System version: Windows 10
* Browser version: Google Chrome 78.0.3904.108 (Build oficial) (64 bits)
* Firebase SDK version: 7.2.2
* Firebase Product: auth, database, storage

### The errors returned by the SDK are only in English

#### Steps to reproduce:

When an error occurs, the SDK returns them only in English.

I imagine it can be complicated to perform this function in the SDK, but I have an idea.

You can provide in the errors documentation page of each product (auth, database, storage) an export option to json format, since all the errors are already listed there, and the user can translate the entire page to whatever language they need. So each user could then export to json and use it for custom mapping code in their code.

#### Relevant Code:

Just an idea for at least have a minimal solution until the sdk could manage multiple languages.

I am talking about this pages, that already exists and can be translated to whatever language

https://firebase.google.com/docs/auth/admin/errors?hl=es-419