Custom javascript files

Enables adding custom javascript files from outside of Horizon

Fixes: bug #1195712

Change-Id: I71fab422f3031259379f1c342897dd4e4f6776c8
update Quantum references to Neutron

implements bug: 1197208

Change-Id: I14de163ca3cf498f5cb738a4c09088bba1759488
Merge "update Quantum references to Neutron"
Merge "Custom javascript files"
Adding configuring hints in Horizon documentation

Fixes bug 1194010

Change-Id: I60e195e8f44cd89ca7ca69a60cd67ed6914a33c7