Use Arel helper methods to generate arel

[kbrock]

Arel provides factory methods to generate common SQL functions

This uses those functions

WIP: I need to ensure that each of these entries are actually being tests. A Quick pass found the coverage pretty high, but I want to do a better job before saying "good"

[kbrock]

update:

• removed methods that generated sql that were only used once
• fixed cop to put parens around a multiplication to make easier to understand

UN-WIP: all virtual attributes had tests.
The only method that was hard to determine test coverage was regional_tenants.
This is tied into Rbac, so should be all set.

[miq-bot]

Checked commits kbrock/manageiq@b3fe70b~...e6b721d with ruby 2.6.10, rubocop 1.28.2, haml-lint 0.35.0, and yamllint
8 files checked, 0 offenses detected
Everything looks fine. 🍪