Search-all slow, inconsistent with previous versions and in some cases completely broken

[tommydeboer]

When using the search bar in the Data Explorer, generally you will find that response times have deteriorated. Some other issues include:

BBMRI: Searching for a biobank ID results in many many results instead of just the one biobank (like it did in 9.0)
Chr6: Searching anything will result in an error that the max query clause count has been reached (defaults to 1024). This value can be bumped by setting the indices.query.bool.max_clause_count property but in this case the query will take more than 30 seconds and it will time out.

Context: sinds ES 7 the _all field has been removed and we've replaced this feature by using multi-match queries.