Adding calculate method to Algorithm, implemented for fidelity key on qpt, adding python example

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>
2 jobs for xacc-devel in 3 minutes and 15 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
failed docker build_devel #387305

00:03:15

failed docker build_devel #387303

00:03:23

 
Name Stage Failure
failed
docker build_devel Build
Appending zipped resources to xacc-ibm
[ 91%] Built target xacc-ibm
[ 91%] Linking CXX shared library libxacc-algorithm-qpt.so
Appending zipped resources to xacc-algorithm-qpt
[ 91%] Built target xacc-algorithm-qpt
Makefile:162: recipe for target 'all' failed
make: *** [all] Error 2
The command '/bin/sh -c git clone --recursive -b xacc-devel https://github.com/eclipse/xacc && cd xacc && mkdir build && cd build && cmake .. -DXACC_BUILD_TESTS=TRUE && make -j$(nproc) install && PYTHONPATH=$HOME/.xacc ctest --output-on-failure' returned a non-zero code: 2
ERROR: Job failed: exit status 1