sysutils/e2fsprogs: port rework

1 - sysutils/e2fsprogs: fix checksum mismatches

e2fsprogs has replaced symlinks by hardlinks in its post-install if
/sbin and ${PREFIX}/sbin were on the same file system, and unless
script processing was defeated on install or upgrade.

Leave symlinks in place to avoid checksum mismatches.

PR: 252184 [1]

2 - add FLAVORS for /sbin handling

• no flavor (default): set symlinks from $PREFIX/sbin to /sbin
• roothardlinks: set hardlinks from $PREFIX/sbin to /sbin, when $PREFIX, its children, and /sbin reside on the same file system
• nobootfsck: do not install into /sbin, but this makes fsck unavailable for ext2/ext3/ext4 file systems before $PREFIX/ is mounted

Require tests on i386 and amd64 only for FreeBSD >= 14 (not >= 12).

Do not print removal advice from post-uninstall on upgrades.