feat: Use CURL multi. #2488

Job	Run time
contract-tests	2m 55s
contract-tests-curl	3m 2s
build-test-client-windows	16m 25s
build-test-client-windows-curl	9m 33s
build-test-curl	5m 57s
build-test-client-mac-curl	10m 18s
build-test	5m 37s
build-test-client-mac	10m 4s
	1h 3m 51s

Provide feedback