Create a link crawler for site

[kexline4710]

Description
We do not have a link checker in place at this time. Some tools that may be useful:

• https://github.com/ChrisWren/grunt-link-checker
• https://github.com/endymion/link-checker
• https://github.com/oscardelben/rawler

Ask
Create a script that can be run on the command line to crawl the links in the application and ensure they are not broken.

Extra Credit: Configure this script to run before and after deployments.

To Do

• Investigate crawling libraries
• Build crawler
• Test command line crawler
• Connect crawler to CI (optional)

[Roenok]

Most of our broken links come from user-generated content, not site deploys, so it might make sense to schedule regular checks rather than just running at build.

[Roenok]

Linking this issue to #402, as we'll need to fix it to get maximum value from any link-checking tool.