utils: remove servlet interaction from PKIResources

got some notes that better to move the code upward into the servlets,
there was an option to add this to ServletUtils but it is way to
specific to do so.

so moving this into servlet and the upcoming registration servlet will
use the same method.

Change-Id: I7b8f18444afd9be981f195e153fd9328d9fc376c
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>