Modify CMakePresets.json to use -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON
in all the presets.
The compile_commands.json file can be used by tools like clangd to get
autocompletion and go-to-definition.
This patch also adds compile_commands.json to the .gitignore, as often
you need to symlink the compile_commands.json from the build directory
into the source directory for it to be picked by tools. That is the case
with clangd at least.
