Give the hp version of VectorTools::project its own file.

Give the hp version of VectorTools::project its own file.

This new file takes about 17 seconds to compile and improves the performance of
the non-hp (i.e., the matrix free) projections a little bit.

before splitting out the hp files:
                                    File name Memory, MB    Time, s
      source/numerics/vector_tools_project.cc       2860         81
source/numerics/vector_tools_project_inst2.cc       2970        100
source/numerics/vector_tools_project_inst3.cc       3956        114

After:
                                    File name Memory, MB    Time, s
      source/numerics/vector_tools_project.cc       2775         79
source/numerics/vector_tools_project_inst2.cc       2882         92
source/numerics/vector_tools_project_inst3.cc       3948        102

These numbers come from setting the C++ compiler as a shell script containing

    /usr/bin/time -v g++ ${1+"$@"}

and then parsing the output.