Load help menu from the default menu

[skateman]

Taking over @martinpovolny's #2192:

• Help menu now defined in the default_menu
• Menu::Item and Menu::Section now specify a more generic link_params instead of an url
• Using the link_params two new link types have been created: modal and new_window

RBAC depends on ManageIQ/manageiq#16003, but its tree hierarchy is described here.

Pivotal story: https://www.pivotaltracker.com/story/show/150933794
@miq-bot add_label enhancement, fine/no

[miq-bot]

Checked commits skateman/manageiq-ui-classic@1051900~...7526130 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
5 files checked, 3 offenses detected

app/presenters/menu/default_menu.rb

• ❗ - Line 280, Col 11 - Style/IndentArray - Use 2 spaces for indentation in an array, relative to the first position after the preceding left parenthesis.
• ❗ - Line 281, Col 147 - Rails/OutputSafety - Tagging a string as html safe may be a security risk, prefer safe_join or other Rails tag helpers instead.
• ❗ - Line 283, Col 9 - Style/IndentArray - Indent the right bracket the same as the first position after the preceding left parenthesis.