Remove MirroredLogger and settings

[Fryguy]

In reviewing our logging in light of the common logging rearchitecture, we found that MirroredLogger is no longer necessary.

• Since it mirrors lines, when we single stream the logs with common logging we end up with duplicate entries.
• The automate log was hardcoded to always mirror at info level, so in speaking with @gmcculloug there should be no problem for them to just look at the automate.log directly.
• I also spoke to @jdeubel directly, and he agreed that the mirroring was no longer needed and in fact, at times, it gets in the way. cc @jcarter12
• I doubled checked the ui-classic code, and there are no UI screens or code related to mirroring. The only way it could have been set in the UI was via the AdvancedSettings, which is yaml driven.

Note that I have PRs for 4 other provider repos to remove the entry from settings.yml, but they are not in the critical path for this PR.

@bdunne Please review

[bdunne]

👍 LGTM

[miq-bot]

Checked commit Fryguy@fb72573 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
4 files checked, 1 offense detected

lib/vmdb/loggers.rb

• ⚠️ - Line 72, Col 5 - Lint/IneffectiveAccessModifier - private (on line 38) does not make singleton methods private. Use private_class_method or private inside a class << self block instead.