Modify logger.py

[Odessit007]

• [x] Add bot_config.json file with the following fields:
• list of pairs to monitor;
• number of top orders to monitor (same for all exchanges);
• path to orders_config.json file
• [x] logger.py should be changed so that it receives parameters from bot_config.json file
• [x] for each exchange and for each currency pair (of course if this pair is traded on this exchange) fetch minimum allowed volume for base and quotation currency
• [x] logger.py should be changed so that it's main part is a function which returns "our generated orders" for the currency pair with maximum possible profit
• [x] logger.py should be changed so that the matching algorithm considers available balance and minimum allowed volumes when generating orders
• [x] logger.py should be changed so that it logs data to remote MongoDB database