Automatically ignore CMake build and install directories

cmake-ignore-build-install.md

This bit of CMake is based off of code from Michael Hirsch (aka @scivision)

# https://www.scivision.dev/cmake-auto-gitignore-build-dir/
# --- auto-ignore build directory
if(NOT EXISTS ${PROJECT_BINARY_DIR}/.gitignore)
  file(WRITE ${PROJECT_BINARY_DIR}/.gitignore "*")
endif()

# Piggyback that file into install
install(
   FILES ${PROJECT_BINARY_DIR}/.gitignore
   DESTINATION ${CMAKE_INSTALL_PREFIX}
   )

presets aren't a cure-all, but they can help avoid the need to use scripts to drive CMake, or excessively long command lines