client: update client-info data for new ifworkers
extension/ibft: Add <client-info> tag
util: Add ni_string_startswith()
xml: Add xml_node_get_next_child()

Function returns next child within same parent node
xml-reader: Add new xml_location_t handling functions

Add new type xml_location_t.
Add new xml_location_t handling function: create, set,
get_filename, get_line
client: Add <client-info> tag and location handling

Support for <client-tag> within all types of config files.
Fill xml_location_t for all types of config files.
Support for show-config's --raw parameter.
fsm: Introduce config origin prioritization

Not to allow overwriting the more important configuration by
less important ones (e.g. firmware by compat) the priorities
have been added. Default is firmware > compat > wicked.
client: Add --force parameter to ifup

Parameter --force allows to overwrite the interface configuration
with lower prio configuration origin.