Implement airport database based on csv OpenFlights table. Implement
UN/LOCODE entry matcher. Implement country namespace.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Define structure of keys and records of the location database. Define the
interfaces of all components necessary for the formation of the database.
Implement the function of filling the database.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>