Remove unreachable trust-checking code and associated machinery

There used to be a time when cf-serverd checked IP reported by the
client and did some trust calculations based on that (including
denying connections from NATed hosts, because NATed hosts didn't
know their IP address as it is seen from cf-serverd side).

In order to overcome NAT issue "skipverify" option has been introduced, to
exclude some IPs/networks from IP/DNS lookup checks.

In CFEngine 3.0 this code became unreachable and stayed like this until today,
and nobody noticed. Hence, it's safe to remove it and deprecate "skipverify"
option.
Merge pull request #1158 from dottedmag/cleanup/remove-server-connection-state-trust

Remove unreachable trust-checking code and associated machinery
Merge pull request #1179 from dottedmag/refactoring/streamline-env-detection

Refactoring/streamline env detection
Declare and initialize Attribute struct wherever possible

This change mostly gets rid of = { {0} } initialization.
Rename confusing variable 'classlist'

It actually holds a monitoring data to be written to the file, so name it so.
Encapsulate EvalContext->eval_options
Group LoadSlowlyVaryingObservations together with other mon-related code
Fix cf-execd not reloading network and monitoring data

Environment reload was a huge bunch of copy-pasted-edited code,
so not all subsequent changes were applied to all agents at once.
Fix it by ensuring all agents unconditionally reload environment
in the same fashion.
Add missing time classes to cf-monitord