Add option to only return gene full text search results that have data

[jonrkarr]

Example:

• K13057: https://datanator.info/gene/K13057/Saccharibacillus%20sacchari

[lzy7071]

I think this is a similar problem with whether to display proteins with no abundance data. Essentially, it's a question of if we should display genes with no

1. Proteins with associated abundance information.
   AND
2. RNA or protein modification information.

We do, however, have information regarding the KEGG group.

Additionally, we won't know if there is RNA modification data until we step into the gene-specific page due to limitations with multi-index ftx. But there may be a workaround

[jonrkarr]

Upon further reflection, I think its informative for Datanator to communicate to users that we don't have data about a specific KO group. This is clearer not being able to render a page for the KO group at all.

As we have discussed previously (KarrLab/datanator_frontend#155), it would be nice to make full text search results with no data optional. As part of this, we would need to add a UI element to the search results page to let users toggle the option. This isn't critical. Lets focus on finishing debugging and come back to this later.