The `fields` option should always return an array for json document fields and single valued field for metadata fields.
Also the `fields` option can only be used to fetch leaf fields, trying to do fetch object fields will return in a client error.

Closes #4542
Do not start packages on installation

The reason to not start packages on installation is to allow to configure
them before starting up (setting heap, cluster.name etc)

Also the documentation was updated in order to show, which statements need
to be executed.
In addition, these statements are also printed out when the package is
installed, depending on whether chkconfig, system or update-rc.d is used.

Closes #3722