Add the following targets in winmake.ps1:
- `installer`: builds the Windows installer
- `docs`: builds the documentation HTML pages
- `validatepr`: runs the Linux Makefile `.valiatepr`
target using podman.
- `lint`: faster validation that runs linter locally
Update of `build_windows.md`:
- removed every reference to the MSYS2 platform
- added instructions to build the installer and linters
Fix https://github.com/containers/podman/issues/21821 and https://github.com/containers/podman/issues/21911
Signed-off-by: Mario Loriedo <mario.loriedo@gmail.com>
