[Documentation]: Split ngx-i18n introduction page into two sections #306

The ngx-i18n page needs to be divided into a For business and a For developers section.

• In the For business section, we explain that the i18n package is used for translation management in a modular and performant way, with ways to prevent translations from being loaded for users that do not have access to those items.
• In the For developers section we use the existing documentation