Infrastructure for templated doc in POD files

Infrastructure for templated doc in POD files

Use new doc-build capabilities
Add -i flag to dofile.
Add doc/man1 to SUBDIRS for the new templated doc files
Rewrite commit a397aca (merged from PR 10118) to use the doc-template stuff.
Put template references in common place
Template options and text come at the end of command-specific options:
opt_x, opt_trust, opt_r (in that order).
Refactor xchain options.
Do doc-nits after building generated sources.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10159)