Add new article button on article editor page

[J16053]

Related Issue

440

Description

Added create new article button identical to the one on the article list page to the article editor page, and updated routes to keep user on the same page upon dialog close.

How Has This Been Tested?

Created test articles from the old button and the new button, navigating both through the article list page and through creating new articles.

Screenshots (if appropriate):

Before:

After:

Checklist:

• [x] My code follows the code style of this project. (see the style guide)
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] Coveralls reported increased code coverage, and full coverage for all the code I added / changed (or I have a good reason that I explained above for why this is not the case)

[coveralls]

Coverage decreased (-0.01%) to 6.951% when pulling cae2759dee0784b747b465a0ffcb08846b950434 on add-new-article-button into efe9a4d95e0becfa4c5b24697d9fa959a8666732 on master.