Fixes #2267 - general rebuild of TFTP, DNS, DHCP

Fixes #10713 - improved backtrace logging

• full trace in 500 page in production shows really the full trace
• Foreman::Logging.exception as an unified entry point for exceptions logging
• the backtrace cleaner doesn't delete the plugins
• the orchestration exceptions gets the backtrace covered by logger...

Fixes #9634 - creating a host with an interface and without os returns a validation message

Fixes #10307 - editing host with 'unattended: false' no longer results in error

fixes #10020 - add next-server/filename attrs to provision NIC DHCP record

A host's DHCP record used to be constructed with PXE attributes in
Orchestration::DHCP, but moved to Nic::Managed during 43c4bd7. Nic::Managed
didn't add PXE attributes, so this commit adds these when provision? is set....

Fixes #1536 - Foreman should check DHCP entries on build.

Fixes #9147 - move managed checks to the start of the DHCP/DNS/TFTP orchestration checks

Refs #3809 - Remove classcheck cop

Refs #3809 - Remove cop IndentationConsistency

Refs #3809 - Remove cops for empty lines

Fixes #7456 - Extract primary interface from host

• Tomas Strachota (tstrachota) <tstrachota@redhat.com>
• Marek Hulán (ares) <mhulan@redhat.com>
• Gregory Sutcliffe (GregSutcliffe) <gsutclif@redhat.com>

All host must have at least one primary interface and one provision (can...

Fixes #7418 - fixed capitalization for some AR errors

Fixes #5637 - Don't raise lease conflicts when reading ad-hoc DHCP leases

fixes #4599 - DNS and DHCP records for BMC and managed interfaces not using FQDN

fixes #4381: dns records are being update after changes to host when dhcp is also present

fixes #1966 - improved UI errors for proxy

fixes #4123 - libvirt imaging support using backing volumes

fixes #2739 - add ActiveSupport::Concern syntax to mixins

fixes #2411 - move files in /models to /concerns, /services, /mailers, /observers