confdata.pm.in: New template for configdata.pm

confdata.pm.in: New template for configdata.pm

To have the configdata.pm text embedded in Configure was kind of ugly,
and becomes clearer if put into a template file, configdata.pm.in.  We
can then use OpenSSL::Template to generate it.

We also modify configdata.pm to be the build file generator, and run
it from Configure.  The benefit with that is that developers who
tinker and play with the build file can do a "factory reset" without
having to go through the configuration process, i.e. they can re-use
the config data the already have.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9693)