feat: allow user to choose build mode: debug (default) or release #134

Job	Run time
deny	47s
docker	16m 39s
lint	7s
build	2m 48s
contract-integration-tests	9m 57s
parachain-integration-tests	1h 53m 15s
coverage	3m 54s
unit-tests	2m 0s
	2h 29m 27s

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