Nano intendation config: migrate to json

• Write json parser using nlohmann-json (example src/input/src) for src/lattice/latticeGenerators/NanoIndentation/nano_indentation_config.h
• Unit test (see: https://google.github.io/googletest/primer.html) analogous to src/input/test/userinput_Test.cc
• Convert test input file in src/test/data
• Provide a converter executable, like done here: src/tools
• Json schema analogous to data/input/userinput.schema.json
• Make sure the json sample is validated against the schema