Allow the user to limit results using a query parameter

[MattiasSp]

Related to origo-map/origo#1413 and origo-map/origo#1418.

As Origo Server admins we can use the default limit config option in dbconfig.js or set a specific limit on the search model to limit the number of hits returned by each search.

It would be great if it was possible for users to request the results with a lower limit than those in the config.

The request could then look like this:
/origoserver/search?limit={max hits per table}&q={defined in dbconfig.js}

The purpose would be to allow the same search endpoint to sometimes return the full search results and sometimes limited search results.

[MattiasSp]

PR incoming.