MT#17673 Move binary files from ngcp-pxe-boot-* packages to 'code' storage '/usr/share/'

The binary files here are release specific,
so it is a 'code' for particular NGCP release.

We cannot store 'code' inside 'data' partition '/var',
otherwise we will have issues on NGCP rollback procedure
which is going to be supported soon.

Change-Id: I627474273b680a7764fb80e6665e83b0c36b0c3f

debian/ngcp-pxe-boot-fs.install

@@ -1 +1 @@
-fs/*            var/lib/ngcp-pxe-boot-images/fs/
+fs/*            usr/share/ngcp-pxe-boot-images/fs/

debian/ngcp-pxe-boot-images.install

@@ -1 +1 @@
-images/*            var/lib/ngcp-pxe-boot-images/images/
+images/*            usr/share/ngcp-pxe-boot-images/images/