Fix descriptions of credentials and verification options for various apps

Fix descriptions of credentials and verification options for various apps

fix doc of s_client and s_server credentials and verification options
fix doc of verification options also for s_time, x509, crl, req, ts, and verify
correcting and extending texts regarding untrusted and trusted certs,
making the order of options in the docs and help texts more consistent,
etc.

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11273)