This commit wraps our xmlrpc functions via configd and wires them via an api controller.
In the long run we should consider moving to RESTful interfaces, but for now we will keep and cleanup the xmlrpc code.
configd action "system ha services_cached" caches the service list for a couple of seconds to improve searchability via our standard grid functions.
At the moment it doesn't seem to make much sense replacing the IXR library, the latest release tag from https://github.com/kissifrot/php-ixr seems to be from a couple of years ago as well and most changes relate to splitting the file into separate class files.
xml-rpc isn't used very often these days, it proably doesn't make sense to try to upstream this change since the library doesn't seem to be very active anymore.
When values are of non string type, it makes sense to trim() for safety, for strings leading spaces can have a meaning.
