Package samba-util-private-headers: Information

- Update to stable release of Samba 4.20
- Add support separate builds generated with samba-pidl.
- Major changes from upstream:
  + dns update debug message is too noisy (Samba#15630).
  + Do not fail PAC validation for RFC8009 checksums types (Samba#15635).
  + Improve performance of lookup_groupmem() in idmap_ad (Samba#15605).
  + Smbcacls incorrectly propagates inheritance with Inherit-Only
    flag (Samba#15636).
  + http library doesn't support 'chunked transfer encoding' (Samba#15611).
  + Provide a systemd service file for the background queue daemon (Samba#15600).

- Update to stable release of Samba 4.20
- Major changes from upstream:
  + The password access tool "samba-tool user getpassword" and the password sync
    tool "samba-tool user syncpasswords" allow attributes to be chosen for output.
  + samba-tool has been extended to provide client-side support for Group Managed
    Service accounts (reading the current and previous gMSA password and writing
    a Kerberos Ticket Granting Ticket (TGT) to a local credentials cache).
  + Windows Search Protocol (WSP) experimental command line client "wspsearch".
  + 'smbcacls' has been extended to allow DACLs to be saved and restored to/from
    a file (in interchangeable format with windows cmd line tool 'icacls.exe').
  + samba-tool now allows users to be associated with claims, the creation and
    management of authentication policies and silos.
  + AD DC support for Authentication Silos and Authentication Policies with
    (functional level must be set to 2012_R2 or later / 2016 latest supported).
  + Support of Conditional ACEs, Resource Attribute ACEs and the Security
    Descriptor Definition Language (SDDL) extensions for conditional ACEs and
    resource attribute ACEs.
  + The Workstation Service Remote Protocol [MS-WKST] calls NetWkstaGetInfo
    and NetWkstaEnumUsers) returns the list of locally logged on users, which
    getting the list from utmp, is not Y2038 safe and has been removed.

- Update to maintenance release of Samba 4.19
- Fixes from upstream (Samba#15580):
  + Packet marshalling push support missing for
     CTDB_CONTROL_TCP_CLIENT_DISCONNECTED and
     CTDB_CONTROL_TCP_CLIENT_PASSED.