Added API and an executable for updating databases
Support for database updates from server
Added actual URL for update
Data Updater: Added writable and default paths for downloading bankdata and reading banks' information
src/include/ktoblzcheck.h.in: Hid the implementation details of the DataUpdater class following the PImpl idiom
updater.cc: Moved DataUpdater implementation to lib directory
WIP: [GSoC 2020]: Provision of bank data in SQLite Format
Updated CMakeLists.txt to run update-database.py at build time