add table UI css, move table and tree mod to core-ui
use tree css, cleanup data explorer css
Merge branch 'feature/genericdataexplorer' of https://github.com/molgenis/molgenis into feature/genericdataexplorer
fix, show expand icons
Merge pull request #1210 from dennishendriksen/feature/genericdataexplorer

Add table UI css, move table and tree mod to core-ui