MINOR: cfgparse-global: move mode's keywords in cfg_kw_list

MINOR: cfgparse-global: move mode's keywords in cfg_kw_list

This commit cleans up cfg_parse_global() and prepares the config parser for
master-worker mode refactoring, where daemon and master-worker fork() calls
will happen very early in init().

So, the config in such case should be read twice:
 - at first: only some keywords in the global section for the mode discovery
   and everything, which is related to master process by opportunity;
 - at second: except the master process, all other keywords would be parsed;