Hardcoded keys on Ruby script

[FrankKair]

The keys are hardcoded in the Ruby script (strings[:"#{key}"] = { :PT => pt, :EN => en, :ES => es }). We should use the keys based on the first row of the XLSX file.

If an user has a XLSX file with the first row as follows:

key en fr sv

We should generate a object like the following:

goodMorning: { en: 'Good morning', fr: 'Bonjour', sv: 'God morgon' }