When using webgrind, use the optional graphviz package for callgraph support

related to https://github.com/opnsense/core/issues/162

was used in some parts for radius, which is still quite messy code and probably not fully functional.

It's actually better to not pull any ABI stuff into a scripting
language.  It's so much easier to work with strings and command
line tooles.  The timing isn't criticial here...

This reverts commit 4df19f1b.
It's time to enable the verification.  the packagaes are being
signed since the original commit went in and all tests have
shown that this works as expected.  Staying safe, you know...

prepare for new mvc framework, we use two different document roots in our new setup to separate legacy and new code.

o Do not keep the login error in the session for
  reloading the page without resubmit will yield
  a spurious login error.

o Pad and reword the message and paint it black,
  eh, red.

Javascript went away, caused error, yadda, yadda...

Next step in integrating our new MVC framework, the mainmenu in the left panel uses the same logic now for both legacy as new content.

- add feature, hide empty items
- configuration in /usr/local/opnsense/mvc/app/models/OPNsense/Base/Menu/Menu.xml

(because if you want /var to be an mfs you can do so)