feature: add support to other languages

[iamgiolaga]

Currently, the bot supports italian language only.

A possible evolution is to add support for other languages. This would imply to:

• add a Telegram command to change the current language: /setlanguage languageCode
• add a column to the all_players db table
• the entire behaviour of the Bot should be based on the current language: the set of users messages should be redesigned and mapped to respective language
• any bot answer should be mapped to the respective language
• bot description should be generalized to english
• commands helper should be generalized to english