Add tutorial on how to build software manually
This MR:
- mentions how to build software using only CMake commands
- makes opinionated recommendations (Ninja on Linux, MSVC on Windows, use only CMake commands, use --parallel and --prefix, prefer build directory inside project source)
- mentions Windows instructions
Why?
- this can be later linked to from other tutorials like KXmlGui, Kirigami, kdesrc-build, Craft and distrobox
- we actually do have KDE developers that do not use kdesrc-build or Craft
- we need a good reference to point new devs to whenever they are in doubt about how to build a project
This MR does not:
- include instructions on building KDE software on Windows without Craft (yes, Craft is that good)
- intend to be a tutorial strictly speaking, but a task-based reference guide (it focuses on how to do what the user likely wants, but does not handhold the developer)
This has been tested on Plasma 6, on a Fedora 40 distrobox on the Steam Deck, and on Windows 11.
Edited by Thiago Sueto