Move the operator<< overloads used by BOOST_CHECK_* out of the
unit test machinery test/setup_common, into test/util/common.h.
And replace the individual per-type ToString() overloads with
a single concept-constrained template that covers any type
exposing a ToString() method. This is important to not add
uint256.h and transaction_identifier.h dependencies to the
shared test/util/common.h file.
Co-authored-by: furszy <matiasfurszyfer@protonmail.com>