Add multilang support, TODO: modify vie.ini

This pull request should allow dynamically setting multiple language for the sites, just modify the `lang/vie.ini` for easy vietnamese version.

For further language addition for the site:

First, add a field into `lang/eng.ini` and all other relevant language such as `vie.ini`, this will be automatically added into the text array. Example:
`text-key-01 = "Hello world!"`

Then in the normal php temple, simply refer to it as:
`<?= lang('text-key-01'); ?>`