Add documentation of maxRamMB for filter cache and query result cache

The query settings in solrconfig page uses LRUCache in the filter cache example. But by default the FastLRUCache is used. Also, SOLR-9633 added support for maxRamMB for filter cache which is not documented at all.

https://builds.apache.org/view/L/view/Lucene/job/Solr-reference-guide-7.1/javadoc/query-settings-in-solrconfig.html