http: replace WorkQueue and threads handling for ThreadPool #885

Job	Run time
macOS native, no depends, sqlite only, gui	46m 13s
macOS native, fuzz	23m 25s
determine runners	3s
Windows native, fuzz, VS 2022	37m 8s
Windows native, VS 2022	1h 32m 56s
test each commit	0s
Linux->Windows cross, no tests	55m 47s
lint	4m 49s
macOS-cross to x86_64	50m 0s
no IPC, i686, DEBUG	1h 18m 31s
ASan + LSan + UBSan + integer	1h 26m 22s
TSan, depends, no gui	58m 51s
fuzzer,address,undefined,integer, no depends	2h 13m 25s
macOS-cross to arm64	51m 59s
Valgrind, fuzz	3h 5m 20s
No wallet, libbitcoinkernel	57m 17s
tidy	1h 50m 20s
previous releases	55m 15s
MSan, depends	1h 21m 47s
MSan, fuzz	1h 43m 46s
32 bit ARM, unit tests, no functional tests	36m 38s
Alpine (musl), depends, gui	1h 12m 26s
Windows, test cross-built	43m 22s
	1d 0h 25m 40s

Provide feedback