New option `-fem` replacing `-nofem` #683

Job	Run time
mmg-debug / ci (macos-13, on, off, on, off, int32_t)	52m 2s
mmg-debug / ci (ubuntu-20.04, on, off, off, off, int32_t)	1h 37m 59s
mmg-debug / ci (macos-13, off, off, on, off, int32_t)	44m 53s
mmg-debug / ci (ubuntu-20.04, on, off, on, off, int32_t)	1h 16m 31s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int32_t)	1h 10m 58s
mmg-debug / ci (ubuntu-20.04, off, off, on, off, int32_t)	1h 2m 4s
mmg-debug / ci (macos-13, on, off, off, off, int32_t)	1h 6m 21s
mmg-debug / ci (ubuntu-20.04, off, off, off, on, int32_t)	5m 11s
mmg-debug / ci (macos-13, off, off, off, off, int32_t)	53m 53s
mmg-debug / ci (ubuntu-20.04, off, off, on, on, int64_t)	1h 12m 41s
mmg-debug / ci (ubuntu-20.04, off, on, on, off, int32_t)	1h 1m 9s
mmg-debug / ci (windows-2022, off, on, off, off, int32_t)	54m 21s
mmg-debug / ci (macos-14, on, on, on, on, int64_t)	6m 58s
mmg-debug / ci (macos-latest, off, off, off, off, int64_t)	2m 45s
mmg-debug / ci (ubuntu-20.04, on, on, on, on, int64_t)	5m 24s
mmg-debug / ci (windows-2022, off, off, off, off, int64_t)	5m 23s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int64_t)	2m 31s
mmg-debug / ci (macos-latest, off, on, on, off, int32_t)	24m 56s
mmg-debug / ci (macos-14, off, off, off, on, int32_t)	5m 40s
mmg-debug / ci (windows-2022, on, off, off, off, int32_t)	54m 42s
mmg-debug / ci (windows-2022, on, on, off, off, int64_t)	5m 4s
mmg-debug / ci (windows-2022, off, off, off, off, int32_t)	53m 28s
mmg-debug / upload_coverage	2m 10s
	14h 47m 4s

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