2nd try to clean URL/options.

SEARCH:
- search.xml: set search path suitable for PMS.
- WebServer: get rid of fake PlexCommand "Search". Search_Result.xml is
processed like any other XML Template.
- XMLConverter: return Search_Results based on path "/search?".
URL/OPTIONS:
- WebServer: separate "PlexConnect" options
- XMLConverter: rely on WebServer's options, rename PlexUDID to
PlexConnectUDID.