Reduce `numbers.hpp` includes with out-of-line definitions #3519

Job	Run time
macOS [TSAN] [lmdb \| clang]	36m 50s
macOS [TSAN] [rocksdb \| clang]	29m 44s
macOS [ASAN] [lmdb \| clang]	31m 12s
macOS [UBSAN] [rocksdb \| clang]	34m 41s
macOS [UBSAN] [lmdb \| clang]	31m 29s
Linux [LEAK] [lmdb \| clang]	44m 34s
Linux [UBSAN] [rocksdb \| clang]	43m 14s
Linux [ASAN] [lmdb \| clang]	41m 32s
Linux [TSAN] [lmdb \| clang]	48m 17s
Linux [UBSAN] [lmdb \| clang]	41m 11s
Linux [ASAN_INT] [lmdb \| clang] (Errors Ignored)	47m 14s
macOS [ASAN] [rocksdb \| clang]	32m 16s
Linux [ASAN] [rocksdb \| clang]	39m 38s
Linux [ASAN_INT] [rocksdb \| clang] (Errors Ignored)	43m 40s
Linux [LEAK] [rocksdb \| clang]	44m 12s
	9h 49m 44s

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