Add a tool to purge archived storages

[agrare]

Storages that aren't connected to any hosts aren't automatically deleted
and thus a tool is needed to clean them up.

This looks for storages which aren't represented in the host_storages
table which means they aren't a part of any EMS and can be removed.

>> Storage.create!(:name => "my storage")
>> Storage.create!(:name => "my other storage")

$ tools/purge_archived_storages.rb
* This is a dry run and will not modify the database
* To actually delete archived datastores pass --no-dry-run

Deleting the following storages:
ID [11] Name [my storage]
ID [12] Name [my other storage]

$ tools/purge_archived_storages.rb --no-dry-run
Deleting the following storages:
ID [11] Name [my storage]
ID [12] Name [my other storage]

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1721612

[miq-bot]

Checked commits agrare/manageiq@f373528~...8e440be with ruby 2.3.3, rubocop 0.69.0, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 2 offenses detected

tools/purge_archived_storages.rb

• ⚠️ - Line 1, Col 1 - Lint/ScriptPermission - Script file purge_archived_storages.rb doesn't have execute permission.
• ❗ - Line 18, Col 53 - Rails/UniqBeforePluck - Use uniq before pluck.

[gtanzillo]

👍

[simaishi]

@agrare "trollop" in hammer branch, FYI.

[agrare]

@simaishi okay I'll make a PR for hammer

[agrare]

@simaishi #18911