8 add helprequest component to storybook along with fixtures

[HarvardWang]

Closes #8

• There is a HelpRequestsTable.js file in frontend/main/components/HelpRequests.
• There is a helpRequestsFixtures.js file in frontend/src/fixtures with an example oneHelpRequest and an example threeHelpRequests.
• There is a HelpRequestsTable.stories.js file in frontend/src/stories/components/Articles.
• In the storybook there is an HelpRequests Folder with a HelpRequestsTable inside with Empty , Three Articles , and Three Help Requests as Admin.
• When Empty is clicked there is a table with all of the headers of an article but with no items in the table.
• When Three Help Requests is clicked there is a table with all of the headers of an article with three items in the table with the correct values corresponding to the values in the articlesFixtures.js file.
• There is a corresponding HelpRequestsTable.test.js that tests HelpRequests.js.

[josiahnross]

LGTM!