delegation: initial support

This patch adds support for grid-site delegation.  The end-point is the
same as the SRM endpoint, so any SRM client can discover the end-point
trivially.
Move auto-generated java to srm-common
Merge branch 'development/delegation' of github.com:paulmillar/dcache into development/delegation

Conflicts:
	modules/srm-server/pom.xml