Pull request #3141: detection: add allow_missing_so_rules

Pull request #3141: detection: add allow_missing_so_rules

Merge in SNORT/snort3 from ~RUCOMBS/snort3:allow_missing_so_rules to master

Squashed commit of the following:

commit 2ad1178e988cef483957cc27644ec6e7f70a1253
Author: russ <rucombs@cisco.com>
Date:   Wed Nov 3 10:14:11 2021 -0400

    build: remove HAVE_HYPERSCAN conditional from installed header

    Installed headers can't have conditional struct members since plugins
    don't have config.h. In this case the hyperscan-related variables are
    now always present.

commit 4d5aa95485dfd13ebad9cec518b92dfedf0b89dd
Author: russ <rucombs@cisco.com>
Date:   Thu Oct 28 09:39:33 2021 -0400

    detection: add allow_missing_so_rules

    By default, missing SO rules cause an error. Set this to true to report
    warnings instead. This is helpful when your rule package is out of date.
    This should not be enabled in a production environment.