Python is not provided with debug libraries, so debug builds are not possible.
Building as RelWithDebInfo will build debug information for the binary, while
using the available release libraries.
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.
