1) Added "interface" AbstractDataSubmitter which is the base class for
all data sending strategies.
2) Added "interface" AbstractJsonDataSubmitter which is the base class
for all JSON sending strategies.
3) Existing data sending functionality is extracted to the
DefaultDataSubmitter class.
4) Simplified existing solution: used built-in redirects resolving
instead of manually implemented.
5) Qt 5.9 is required.