cmake: name the Unix binary winuae

cmake: name the Unix binary winuae

The installed Linux command, the .desktop entries, and the WinUAE.app
bundle all use the name winuae while the build tree produced
winuae_unix. Set OUTPUT_NAME on the winuae_unix target so the binary is
winuae everywhere, drop the now-redundant install RENAME, and update
the smoke script defaults, bundling scripts, and README accordingly.
macos-bundle.sh keeps a fallback for build directories from before the
rename. The CMake target names are unchanged.