Decompile ALL functions please!

I want retdec to decompile all functions at once. Those functions could be saved in several C files. It will be easier to do the code navigation using a code editor like vscode.

Currently, retdec only decompiles `main()`, not the whole program.

Thanks!

Start at RetDec's existing decompilation entry point for main() and trace how the current output is assembled. Define how all functions should be discovered and whether they belong in one or several C files, then validate that the generated files support navigation in an editor such as VS Code.

Written by the indexing model from the issue text.