Move contents of frontier-squid-utils proto_install to RPM spec file

The proto_install target of the frontier-squid-utils makefile prepared prototype files for building by the RPM. The RPM spec file then completed processing and moving the files to their proper locations. This split responsibility meant that changes to the locations of the target files could require changing both the tarball and the RPM spec file.

To simplify future maintenance, all the details of the processing of these files has been moved to the RPM spec file (merge request #4). The proto_install target is being retained in case there is some future need to do some special processing or compilation of code in preparation for the RPM.