Update nokogiri gem when installing deface-based plugins

deface < 1.0 has a dependency on ~> 1.5.0 which conflicts
with the 1.6.x gem installed by default in core.
update foreman_discovery to 1.3.0 rc3
Update to foreman_bootdisk 2.0.7
Update to foreman_bootdisk 2.0.8
discovery: release 1.3.0
hammer-cli updated to 0.1.1
hammer-cli-foreman updated to 0.1.1
Pin librarian on as it's now 1.9 only
core/proxy/installer: release 1.5.1
Add debs for puppetdb_foreman

Fix changelog to puppetdb-foreman
Release 0.0.7
update foreman_dhcp_browser to 0.0.5
core/proxy: release 1.5.2