Significant strongswan plugins aren't packaged

Strongswan has a number of plugins for its crypto that could be easily packaged but currently are disabled. This includes botan, wolfssl, the unbound resolver and TPM support. All dependencies are already in the repos, so these should be activated.

Note that wolfssl requires the WOLFSSL_KEYGEN option to be set in the package in order to build, so that would need a slight adjustment. (There are some more options like WOLFSSL_DTLS etc. that should maybe be activated in that package, but that's its own issue)

(newhope and ntru were removed with 6.0, so these options are redundant now)