(mvc) add AuthenticationServerField type to model, to select authentication servers (which only exists in the legacy data)

PR: https://redmine.pfsense.org/issues/3670

Switch to GET for now, I think other pages use a mix of POST and GET
in case of 'clear' which doesn't clear the right log for obvious
reasons...

(captive portal) work in progress rewrite captive portal feature using new framework and standards... lots of things to do here, but we've started.

(ui) add tokenizer support on edit in UIBootgrid, eventually we should probably break up this wrapper a bit more. it works, but feels a bit too complicated.

(mvc) remove previous sample from codebase, the helloworld plugin covers more. leave template sample in place, because it provides some additional options of the framework.

Thin out "Status" and "Diagnostics" white at it, although the
overall static page conception isn't consistent at all.  Not
liking this, but something has got to be done.  Won't be the
last commit I think.  :)

(legacy) replace time with microtime in make_config_revision_entry, not needed for the config revision anymore because that method uses it's own timestamp. Revision entries are also used on some other config items, like firewall rules.

(mvc) add default config revision if none is given, fix for https://github.com/opnsense/core/issues/386