This new scanner type uses OpenVAS scan configs and connects to an OSP
scanner (ospd-openvas).

OSP expects boolean preferences to be 1 or 0 instead of "yes" or "no"
and only the selected value for selection preferences.

Without this OSP tasks had to wait until the end of the scan before
fetching any results, which could take a long time for scanners like
the OpenVAS one and tasks with many target hosts.

This parses results with the "general/Host_Details" port as host details
as it is done in OTP.
This should eventually be handled by the "Host Detail" result type once
there is a well-defined way to handle the source info in OSP.

The credentials for OSP scans are adjusted for the change in gvm-libs to
use the new method of storing the authentication data like username
and password.

This allows using SSH private key authentication in OSPd-OpenVAS scans.

The osp_scanner_connect function will no longer try to get the port,
ca_pub, key_pub and key_priv from the scanner as they are not needed
and getting the private key could fail if the scanner has no credential.

OSP results with "HOST_START" and "HOST_END" as NVT id will be used to
set the start and end time of a host.

The parse_osp_report() function will now get the hostname attribute from
OSP results and make_osp_result() will store it in the results table.

The OSP-OpenVAS scanner type is removed again in favor of running all
OpenVAS scans via OSP instead of OTP.

The process running the function may not have global_current_report set,
so the current report has to be fetched from the task.

The osp_start_scan_ext function has been changed to have most options
passed in as a new struct type (osp_start_scan_opts_t).

The osp_scanner_connect function will now log a warning message
containing the hostname or socket path.

The variables start_time and end_time in the parse_osp_report function
and rc in the handle_osp_scan function were not initialized.