Control LIMIT in run mode

[mkroetzsch]

When running a query directly using the run parameter, the LIMIT is part of the query string. It would be better if this would be controlled by the UI, so that one can also offer to show either some or all results. It could be useful if one could set the initial LIMIT through a URL parameter too, since 10000 may not always be useful/necessary as a default, depending on the query.

When linking to query.wikidata.org as per #55, a reasonable limit should be picked specifically for this UI (maybe 1000, since hte browser tends to get very slow with very many results there). This does not need to depend on the current limit in our query view.