Port PAM module from gnome-keyring

See ModularGnomeKeyring Fedora change proposal for background information.

TODO:

• port PAM module form gnome-keyring
• decouple unrelated gnome-keyring implementations from PAM implementation
• remove existing tests
• implement the new PAM tests based on pam_wrapper and libpamtest.
  • mock the control socket.
  • PAMTEST_AUTHENTICATE
• update CI.
• remove start_daemon and dependents.
• separation of commits

New changes introduced to the PAM module:

• Removed start_daemon and the dependent code altogether. Because, gnome-keyring-daemon is launched by systemd.
• Replaced calls to pam_get_item to retrieve authentication tokens with pam_get_authtok.

PAM module test results summary:

• GNOME OS Nightly :
  • Unlocks the default keyring during boot.
    • changes made to /lib/x86_64-linux-gnu/security/ do not persist after a reboot.
  • Unlocks the default keyring during logout/login.
• Debian 12.2 :
  • Unlocks the default keyring during boot.
  • Unlocks the default keyring during logout/login.
• Fedora 39 :
  • Unlocks the default keyring during boot.
    • gkr-pam: unable to locate daemon control file
    • this could be due to some configuration issue.
  • Unlocks the default keyring during logout/login.