ENT-12414: Use `librsync`'s Stream API in `GET <FILENAME>` requests #1651

Job	Run time
shellcheck_tests / Run shellcheck on shell scripts	1m 1s
unit_tests / Run Unit Tests	3m 55s
windows_acceptance_tests / windows_acceptance_tests	6h 0m 11s
macos_unit_tests / macos_unit_tests	2m 47s
asan_unit_tests / asan_unit_tests	2m 49s
acceptance_tests / acceptance_tests	31m 29s
static_check / static_check	2m 51s
valgrind_check / valgrind_check	5m 23s
valgrind_tests / valgrind_tests	5m 45s
	6h 56m 11s

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