Issue 1612 - clean up codes to share common codes.

[gcheung-SF]

@bryanwulf , this is just to clean up duplicated codes so can be reviewed/merged any time. Thanks.

[gcheung-SF]

Steps to test changes:

1. Log in as yourself or associate yourself with affiliation.
2. Create a new Gene-Disease Record.
3. Add multiple articles by PMIDs.
4. Create different evidences for the articles.
5. Click on "Preview Evidence Summary" button on top of the GDM page.
6. In each table, click on the up/down arrows in sortable column headings to test sorting.