MDEV-30836 run_test_server() refactored

run_test_server() is actually manager main loop. We move out this
function into Manager package and split into run() and
parse_protocol(). The latter is needed for the fix. Moving into
separate package helps to make some common variables which was local
to run_test_server().

Functions from the main package is now prefixed with main:: (should be
reorganized somehow later or auto-imported).