[doc][daemon-fix][daemon-opt] Known limitations updated, code fixes, clean-ups, optim...

[doc][daemon-fix][daemon-opt] Known limitations updated, code fixes, clean-ups, optimizations, formatting

- org.freedesktop.DBus.GetNameOwner fixed
- added policy checking when acquiring well-known name
- dbus_connection_get_unix_user rewritten for kdbus
- dbus_connection_get_unix_process_id rewritten for kdbus
- bus_service_get_primary_owners_connection extended with kdbus support
- (kdbus_get_connection_unix_) user and process_id refactored for more universal usage
- kdbus_list_services optimized

Change-Id: I90896df7bebafe05869778da1aef2a22a24722fe
Signed-off-by: Radoslaw Pajak <r.pajak@samsung.com>