Document / point to `path_search` rippled.cfg options

[ximinez]

Per https://github.com/ripple/rippled/issues/4141, rippled recently reduced the default values of the path_search-related configuration options to lower memory consumption. It might be helpful to document and/or point out these options on the pages that document path finding and/or server config for operators who desire the old behavior, which was able to find longer paths, even though it consumed more memory.

[mDuo13]

I agree it would be a good idea to add a new page or tutorial clarifying how & why a server operator may want to increase or decrease the path search setting on their server.