Integrated Gallery into DataCultures: images and videos load properly

https://jira.ets.berkeley.edu/jira/browse/CYB-80

Initial integration of Gallery into DataCultures

Styling will be completely revamped by @ericayin, at the moment only functionality is of core value
@NolanChan can you make the extension of the jpeg images `.jpg` instead?
Also make sure to run them through imageoptim https://imageoptim.com/ - binary files will make our git workflow quiet a lot slower, so let's keep them as small as possible.