Graphql - Normalize epic complexity multiplier

Currently we allow to load up to 2000 epics per group - I think this is for now because of epic roadmap which doesn't support pagination yet(?). When evaluating query complexity we take into account also number of iteams which can be theoretically loaded - such limit is typically maximum page size (100) so if the default multiplier is 0.01, then the resulting complexity is typically increased twice (at max). But if the limit is 2000, then complexity is increased 20 times, which causes that the query which loads group epics exceeds our default 200 max complexity limit. For now 0.001 limit is set for group's epic resolver, but it would be better to decrease page size back to 100 and then we can remove this multiplier.