* kbx/keyboxd.h (struct server_control_s): Replace the two request
objects by just one.  Add filter flags.
* kbx/kbxserver.c (cmd_search): Add options --openpgp and --x509.
(cmd_killkeyboxd): Do not return GPG_ERR_EOF.
* kbx/frontend.c (kbxd_release_session_info): Adjust for the new
request object.
(kbxd_search, kbxd_store, kbxd_delete): Ditto.
* kbx/backend-sqlite.c (struct be_sqlite_local_s): Add filter flags.
(run_sql_prepare): Add optional arg 'extra'.  Change callers.
(run_sql_bind_ntext): New.
(run_sql_bind_text): Just call run_sql_bind_ntext.
(run_select_statement): Add ctrl arg.  Implement the filter flags.
* g10/call-keyboxd.c (keydb_search): Use the --openpgp option.