MFC r326738: pw(8): correct expiration period handling
and command line overrides to preconfigured values for -e, -p and -w flags.

Use non-negative symbols instead of magic values
in passwd_val/pw_password functions.

PR: 223431
Submitted by: Yuri Pankov (in part, patch for the manual)
Approved by: mav (mentor)
Relnotes: yes

MFC r312644, r312650

r312644:
Readd a feature lost in pw(8) refactoring

pw usermod foo -m

It used to be able to (re)create the home directory if it didn't exists

r312650:
Really restore the old behaviour for pw usermod -m

It again reinstall missing skel files without overwriting changed one
Add a regression test about it

PR: 216224
Reported by: ae

MFC: r285133,r285136,r285137,r285156,r285157,r285158,r285256,r285318,r285395,
r285396,r285398,r285401,r285403,r285405,r285406,r285408,r285409,r285411,
r285412,r285413,r285415,r285418,r285430,r285433,r285434,r285442,r285948,
r285984,r285985,r285989,r285996,r285997,r286045,r286047,r286066,r286150,
r286151,r286152,r286154,r286155,r286156,r286157,r286173,r286196,r286197,
r286198,r286199,r286200,r286201,r286202,r286203,r286204,r286210,r286211,
r286217,r286218,r286258,r286259,r286341,r286775,r286982,r286986,r286991,
r286993

Validate most pw inputs.
Rewrite the way parsing sub arguments is made to simplify code and improve
maintenability
Add -y (NIS) to userdel/usermod
pw userdel -r <rootdir> now deletes directories in the rootdir
Only parse pw.conf when needed
Reject usermod and userdel if the user concerned is not on the user database
supposed to be manipulated

MFC: r285133,r285136,r285137,r285156,r285157,r285158,r285256,r285318,r285395,
r285396,r285398,r285401,r285403,r285405,r285406,r285408,r285409,r285411,
r285412,r285413,r285415,r285418,r285430,r285433,r285434,r285442,r285948,
r285984,r285985,r285989,r285996,r285997,r286045,r286047,r286066,r286150,
r286151,r286152,r286154,r286155,r286156,r286157,r286173,r286196,r286197,
r286198,r286199,r286200,r286201,r286202,r286203,r286204,r286210,r286211,
r286217,r286218,r286258,r286259,r286341,r286775,r286982,r286986,r286991,
r286993

Validate most pw inputs.
Rewrite the way parsing sub arguments is made to simplify code and improve
maintenability
Add -y (NIS) to userdel/usermod
pw userdel -r <rootdir> now deletes directories in the rootdir
Only parse pw.conf when needed
Reject usermod and userdel if the user concerned is not on the user database
supposed to be manipulated