Adapt existing study page to show all studies, and specific study types

[ljwh2]

User story:

As a user, I want easy access to browse all studies in the Catalog, and to be able to see GxE studies only. I want this to be presented on a separate page, https://www.ebi.ac.uk/gwas/studies/. The link to the studies page should be presented on the search results page https://www.ebi.ac.uk/gwas/search with text “Browse all studies”. On the studies page, I want to be presented with a table of all studies in the same format/style as on the Trait pages. I want to see a second table containing only studies with the GxE flag. This could be presented similarly to associations, studies, sumstats tables on the other pages. A third table could be added called “seqGWAS”, including only studies with “Whole genome sequencing” or “Exome-wide sequencing” in the genotyping_technology field. Note that some studies contain multiple genotyping technology types. For preference, the table should exclude any studies with any other genotyping technology, so a study with “Whole genome sequencing | Genome-wide genotyping array” would be excluded, but “Whole genome sequencing | Exome-wide sequencing” would be included. However, if this is difficult to implement, we can discuss.