Add configuration of coding style to Project settings

[humdingerb]

The "Format" menu item works, if there is a .clang-format file in a project's top folder.

However, if there is no .clang-format file, some formatting is applied, though I'm not clear what defaults are used. The indention is changed to two spaces instead of a tab, for example.

I think it would be best to have the user configure this in the "Project settings". There could be a pop-up menu "Use coding style:" and the options "none", "Haiku" and "from Project".

If there's no .clang-format file in the project's top folder, disable "from Project" and make "none" the default. In that case, disable "Edit|Format". Otherwise default to "from Project".

The menu could be renamed to "Apply coding style" which is more decriptive.

[Freaxed]

The default is the "LLVM coding style".
Keep in mind that 'Format' is a LSP command (https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_formatting) and depends on the LSP in use for a specific file. For example pylsp (lsp server for python) has a different default style and a different config file... So the configuration must be per lsp server. Another point is that the "Haiku format" is not exactly following all the haiku rules (only with the haiku-format tool you can have it but is an external tool).