Simplify doc target.
Delete redundant doxygen configuration.
Keep only relevant doxygen configuration.
Delete unneeded extern specifier in internal headers.
Split neardal_mgr_record_get_tag().
Return success if error code is required.
Reuse neardal_mgr_tag_search().
Minor fixes.
Add record converter functions.
Simplify tag write.
Reuse record convevter.
Simplify device push.
Remove unneeded code.
Remove unneeded code.
Remove unneeded fields.
Update record's interface description.
Minor fix.
Remove unused fields.
Don't subscribe DBus.Properties for record.

Writing a record deletes it, so subscribing to DBus.Properties
interface looks redundant.
Add GVariant convenience functions.