refactor, misc: remove CBitcoin(Address|Secret) #3105

Job	Run time
Lint	48s
ARM [GOAL install] [buster]	12m 24s
Win32	14m 20s
macOS 12 native [GOAL install] [GUI] [no depends]	14m 36s
Win64	32m 4s
i386 Linux [GOAL install] [focal]	12m 57s
x86_64 Linux [GOAL install] [GUI] [focal] [no depends]	16m 34s
x86_64 Linux [GOAL install] [GUI] [bionic] [no depends]	15m 44s
x86_64 Linux [ASan] [LSan] [UBSan] [integer] [jammy] [no depends]	19m 1s
macOS 10.14 [GOAL deploy] [GUI] [no tests] [focal]	34m 15s
	2h 52m 43s

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