REST cluster state API: Improved consistency

Instead of specifying what kind of data should be filtered, this commit
streamlines the API to actually specify, what kind of data should be displayed.

A small feature has been added as well: If you specify an index to select on, not
only the metadata, but also the routing tables are filtered by index in order
to prevent too big cluster states to be returned.

Also the CAT apis have been changed to only return the wanted data in order to keep
network traffic as small as needed.

Tests for the cluster state API filtering have been added as well.

Note: This change breaks backwards compatibility with 0.90!

Closes #4065