normalizing time config entries: use time abbreviation (str2seconds) for all time options such 'dbpurgeage', 'bantime', 'findtime', ex.: default '1d' instead '86400';
code review and test case extended;
fix: fail2ban-regex with filter file failed (after merging #824, because test case missing);
test case for 'readexplicit' added;
Merge remote-tracking branch 'remotes/origin/_tent/cache-config-read-fix1' into ban-time-incr