Relates #29827
This implementation behaves like the current transport client, that you basically cannot configure a Watch POJO representation as an argument to the put watch API, but only a bytes reference. You can use the the `WatchSourceBuilder` from the `org.elasticsearch.plugin:x-pack-core` dependency to build watches.
This commit also changes the license type to trial, so that watcher is available in high level rest client tests.
/cc @hub-cap
202894b832