Launch molecular data queries beta

[tsliaw]

@john-conroy Feel free to add more to this task list, but I'm adding some of the basic things here as a github issue as a tracker.

• Add molecular data queries to Other dropdown in header. See screenshot below. Figma
• Add molecular data query slide to homepage carousel. (I will update with screenshot and description text in a bit).

[tsliaw]

Title: Discover HuBMAP data from molecular and cellular information

Description: Explore our new beta feature of a molecular data query that can retrieve datasets based on abundance of transcriptomic, epigenomic, and proteomic biomarkers across cells.

Image is located in drive as molecular_data_query.png. Screenshot shown below. When you implement this, can you let me know what this looks like before merging? I'm a little hesitant given the screenshot I just gave you has the same background color as the homepage background, so I might need to change the image to be better fitted for the homepage.