Expose additional component related metadata for manageContent tag

The new manageContent tag should expose additional metadata related to the componentParameter:

• componentValue: the value of the componentParameter, either a relative or an absolute path
• componentPickerConfiguration: The root path of the CMS configuration to use for the picker, relative to /hippo:configuration/hippo:frontend/cms.
• componentPickerInitialPath: The initial path to use in the picker if nothing has been selected yet
• componentPickerRootPath: the absolute root path to use in the picker, or an empty string if the channel content path is used
• componentPickerRemembersLastVisited: Whether the picker remembers the last visited path
• componentPickerSelectableNodeTypes: Types of nodes to be able to select in the picker.