"Jack of all trade but master of none" means that this person can do many things, but in all of the things he does, he only does them averagely. "Give a d*m* sort of person" I haven't heard of personally but "give a d*m*" is a more vulgar way of saying care so it would probably mean the sort of person that cares

'Jack of all trades but master of none' is a saying which means that the person knows a little bit about lots of things, but unfortunately does not have enough knowledge about anything to make them a 'master' or an expert. 'Give a damn' is a phrasal adjective which means that the person doesn't let things stress him. Or it could also mean someone who doesn't care about the worries or problems of another person.