Refactor key generation classes #3810

Job	Run time
cmake-offline-googletest-src	4m 8s
ubuntu-latest [CC gcc; botan; shared libs on; GnuPG stable]	4m 3s
ubuntu-latest [CC clang; botan; shared libs on; GnuPG stable]	4m 24s
ubuntu-latest [CC gcc; openssl; shared libs on; GnuPG stable]	4m 10s
ubuntu-latest [CC clang; openssl; shared libs on; GnuPG stable]	3m 59s
ubuntu-20.04 [CC gcc; openssl; shared libs on; GnuPG stable]	4m 29s
ubuntu-latest [CC gcc; botan; shared libs off; GnuPG stable]	4m 7s
cmake-offline-googletest	4m 14s
system-sexpp, sexpp shared libs on, rnp shared libs on	2m 50s
system-sexpp, sexpp shared libs on, rnp shared libs off	2m 59s
package-source	28s
system-sexpp, sexpp shared libs off, rnp shared libs on	2m 51s
system-sexpp, sexpp shared libs off, rnp shared libs off	2m 46s
package	48s
debian-tests	47s
	47m 3s

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