Refactor pgp_key_search_t #596

Job	Run time
Windows-2019 [arch x64, toolset v142, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	13m 20s
Windows-2019 [arch x64, toolset v142, backend botan, build shared libs off, use CMake prefix path off, sanitizers off]	13m 39s
Windows-2019 [arch x64, toolset v142, backend openssl, build shared libs off, use CMake prefix path on, sanitizers off]	12m 8s
Windows-2019 [arch x64, toolset v142, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	13m 43s
Windows-2019 [arch x64, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	20m 47s
Windows-2019 [arch x64, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path off, sanitizers off]	17m 54s
Windows-2019 [arch x64, toolset ClangCL, backend openssl, build shared libs off, use CMake prefix path on, sanitizers off]	15m 23s
Windows-2019 [arch x64, toolset ClangCL, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	16m 1s
Windows-2019 [arch x64, toolset v142, backend botan, build shared libs off, use CMake prefix path off, sanitizers on]	27m 35s
Windows-2019 [arch Win32, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	17m 19s
Windows-2019 [arch Win32, toolset v142, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	16m 24s
	3h 4m 13s

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