[C++][FlightRPC] ODBC: Replace boost::variant with std::variant

[alinaliBQ]

Describe the enhancement requested

AC:

Replace boost::variant with std::variant in ODBC.

Example of boost usage to be removed:

arrow/cpp/src/arrow/flight/sql/odbc/odbc_impl/spi/connection.h

Lines 65 to 66 in e11aeee

	typedef boost::variant<std::string, void*, uint64_t, uint32_t> Attribute;
	typedef boost::variant<std::string, uint32_t, uint16_t> Info;

Component(s)

FlightRPC, C++