Issue 494: Provide a link to a wiki page on Github regarding search help.

[kaladay]

Description

Opted to use an icon to fit in with the current available space.

The URL is exposed via the new URLs appConfig setting:

• searchHelpManageUrl
• searchHelpDismaxAndUrl
• searchHelpDismaxOrUrl
• searchHelpEdismaxAndUrl
• searchHelpEdismaxOrUrl
• searchHelpLuceneAndUrl
• searchHelpLuceneOrUrl

The help only appears on the non-everything searches in the Discovery View pages.

In the management of Discovery View, a help link is added as a sentence at the bottom of each modal.

The changes on the github wiki are to be updated separately.

Fixes #494

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• [X] Manually.

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] My changes generate no new warnings
• [x] New and existing unit tests pass locally with my changes

[coveralls]

Coverage: 45.337% (+0.09%) from 45.242% when pulling 225c306862e69375e96f868e65e46c4d5117af75 on 494-document_search into 1b696f319701dad2e50bee256e71e401b17fb7da on staging.