Add some hardened configs to test

[mjeveritt]

https://www.openwall.com/lists/kernel-hardening/2018/07/18/1 has some useful defconfigs making use of well-known existing hardening features/options which we could easily deploy in kernel testing.
These could be potentially added under a 'hardened' USE flag with reference to the upstream inspirations in ewarn/einfo messages.

[aliceinwire]

I would like to also add https://liquorix.net configs also

[aliceinwire]

what do you suggest for keeping different configuration tests on Buildbot?
using build tags maybe ? or making a different build for each different configuration.
A different build for each different configuration can be a bit chaotic.
Any idea on how to add more configurations testing but keep builders clean?.

[aliceinwire]

would be happy to have this implemented, but currently we are favoring gentoo kernel team stabilization cases.