Fixes #13725 - DHCP MAC conflicts are reported

(cherry picked from commit 4c9529c7bc3c081fb3d0bfdbee09b2e7d6eabc0a)

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 #8727 - DHCP validation does not fail on discovered leases

Refs #3809 - Enable cop StringConversionInInterpolation

Fixes #7971 - DHCP hostname commutative conflict fix

Refs #3809 - Use parentheses in method definitions

Refs #3809 - Remove rubocop TODOs

Removed the following TODOs so that cops for these will run from now on:

Lint/AmbiguousOperator, DefEndAlignment, DeprecatedClassMethods
EnsureReturn, RequireParentheses, Void, BlockAlignment, EndAlignment,
UselessAccessModifier,...

Fixes #5941 - Handle nil comparison object in DHCP::Record.valid?

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

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