Added org.apache.commons.collections4 as external component.

Added org.apache.commons.collections4 as external component.

This change also removes org.apache.poi.{,ooxml,ooxml-schemas} from the
external components as preparation for including manually bundled
org.apache.poi bundle version 3.15.0. org.apache.commons.collections4
was added because it is a dependency of this new version of POI.

Due to org.apache.poi.{,ooxml,ooxml-schemas} containing split packages
it is just easier to bundle the POI JARs into a single bundle to keep
bundle class loading happy.

refs #6813

Change-Id: Iefd4b52c0fafc4a0e7b6b9ed2bf6bac0e38a113e