New Tree view as a tab in home page to navigate resources as a hiearchical tree (spaces, collections, datasets, folders and files). The tree is lazily loaded using a new endpoint `api/tree/getChildrenOfNode`.
Added a max of 100 status messages on the page listing all extractions. Before trying to list all extractions in the system was causing the JVM to run out of memory. The link to the page in the admin menu was remove, but the page is still there for future improvements.
