Better Editor Support of Firmware C++

[hekno25]

Currently the firmware part of the project doesn't work with the clangd LSP server. LSP servers provide IDE-like features to many editors such as VSCode (with the clangd extension in this case), Neovim, Emacs, etc. In order to work with a C/C++ project, clangd needs a compilation database file.

SCons can generate this file automatically, but it needs to be at least version 4.0. If we bump SCons from version 3.1.2 to 4.0 or higher, we could modify the SCons build scripts to generate the compilation database.