Added container for Ks LL candidates without any pT cut on the daughters

See https://its.cern.ch/jira/browse/LHCBPS-1809.

As discussed on the mailing lists, see https://groups.cern.ch/group/lhcb-davinci/Lists/Archive/Flat.aspx?RootFolder=%2Fgroup%2Flhcb%2Ddavinci%2FLists%2FArchive%2FInefficient%20cut%20in%20StdLooseLambdaLL&FolderCTID=0x01200200B795ECDBD8943F4E90E5F02A017196C9, we can quite some efficiency for V0 LL candidates by not including the standard PT > 250 MeV requirement as for regular long track candidates. For Lambda's, there is a StdVeryLooseLambdasLL container that does just that. However, for Ks'es, there is no container, which this merge request aims to correct.

Just a general question, not having developed for DaVinci before: what is the best way to test this container? Thanks in advance!