Implement rendering pins for submap links to maps with at least one searched element
What has been done:
submap connections state management
selectors for finding number of active elements per map and submap links for render
rendering of submap links pins
unit tests
Important:
Why getSubmapConnectionsBioEntity reducer is implemented weird way? Because adding submapConnections as required field would also imply fixing >85 different tests which I've viewed as more dangerous than defining this field as optional with additional actions made in the reducer
This PR is based on !163 (merged) so some changes may not be relevant to submap connections feature if !163 (merged) is not merged
