Feature: Add file types for APIs that support file translation

[tovmasharrison]

Currently, inside apis.json, file_translation: true is given for APIs that support file translation.

1. Instead of giving a boolean value, we can just add the file types each API supports. For example: file_translation: [XML, Text, Markdown]

2. Afterward, in api.html, we can have a list of types and just put it in the infobox:

File types: ...