Inline buildPointSeriesData and buildHierarchicalData dependencies

[flash1293]

discover and vis_type_vislib are still relying on the ui/agg_response helpers buildPointSeriesData and buildHierarchicalData. As these are not going to get migrated, it makes sense to inline them into their respective plugins because of limited usage and the plan to mid-term migrate away from both of these.

Tasks:

• Move buildHierarchicalData to vis_type_vislib (as it's the only user)
• Move buildPointSeriesData to vis_type_vislib
• Move the relevant parts of buildPointSeriesData to discover - the logic can be extremely simplified for the discover case because the shape of table and agg configurations is always constant and only uses a subset of the functionality of buildPointSeriesData: https://github.com/elastic/kibana/blob/master/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/discover.js#L852 Check src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/histogram.tsx for the relevant attributes

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)