Enable queued credentials validation for middleware

[tumido]

Allow Middleware to have validated credentials via queued job instead of realtime.

This is an umbrella PR for all related commits

Merge/backport together with (in this order):

1. Enables both workflows on provider Add optional validate param to raw_connect manageiq-providers-hawkular#100
2. Fixes SSL certificate handling for new wokflow Create cert_store if it's not created before validation manageiq-providers-hawkular#101
3. Provides mapping to UI for new workflow Fix credential validation in Hawkular provider about number of arguments #2577

By merging the dependent PRs both credential validations are possible. Merging this umbrella PR provides a switch between old and new workflow.

[tumido]

cc @abonas, @agrare

[miq-bot]

Checked commit tumido@091e257 with ruby 2.3.3, rubocop 0.47.1, and haml-lint 0.20.0
1 file checked, 0 offenses detected
Everything looks fine. 🏆

[abonas]

@miq-bot add_label middleware

[abonas]

@miq-bot add_label enhancement

[abonas]

@miq-bot add_label gaprindashvili/no

[chessbyte]

Closing since middleware provider is not supported