GH-5149 Lucene numdocs param

[ate47]

GitHub issue resolved: #5149

Briefly describe the changes proposed in this PR:

I added a virtual property to specify the maximum amount of results the user wants in a LuceneSail search.

For example, with the example in rdf4j.org it gives something like that:

PREFIX search: <http://www.openrdf.org/contrib/lucenesail#>

?subj search:matches [
	      search:query "search terms...";
	      search:numDocs 200 ] .

At the same time, I added the sail parameter maxQueryDocuments to set the maximum amount of documents the user can query. By default, it takes the value of maxDocuments to keep a backward compatibility.

LuceneSail lc = new LuceneSail();
lc.setParameter(LuceneSail.MAX_QUERY_DOCUMENTS_KEY, "200");

---

PR Author Checklist (see the contributor guidelines for more details):

• my pull request is self-contained
• I've added tests for the changes I made
• I've applied code formatting (you can use mvn process-resources to format from the command line)
• I've squashed my commits where necessary
• every commit message starts with the issue number (GH-xxxx) followed by a meaningful description of the change

[hmottestad]

This looks very good. Thanks for the tests!

I've added some comments. In particular I'm a bit unsure about the introduction of a second max config option.