Rename to Luanti (#15294)

The new header intentionally isn't in MTG stone design (or any other MTG-esque design), since we want to distance Luanti and MTG from each other. The font "undefined medium" (https://undefined-medium.com/) was used. 

ASCII art generated by https://patorjk.com/software/taag/#p=display&f=Graffiti&t=luanti
https://github.com/minetest/minetest/pull/11952#issuecomment-1013364703

---------

Co-authored-by: sfan5 <sfan5@live.de>

.github/workflows/windows.yml

@@ -56,8 +56,8 @@ jobs:
         run: |
           dest=$(mktemp -d)
           unzip -q -d "$dest" B/build/*.zip
-          cd "$dest"/minetest-*-win*
-          wine bin/minetest.exe --version
+          cd "$dest"/luanti-*-win*
+          wine bin/luanti.exe --version
 
       - uses: actions/upload-artifact@v4
         with:
@@ -103,7 +103,7 @@ jobs:
           vcpkgGitCommitId: ${{ env.VCPKG_VERSION }}
           vcpkgTriplet: ${{ matrix.config.vcpkg_triplet }}
 
-      - name: Minetest CMake
+      - name: CMake
         run: |
           cmake ${{matrix.config.generator}}  `
           -DCMAKE_TOOLCHAIN_FILE="${{ github.workspace }}\vcpkg\scripts\buildsystems\vcpkg.cmake"  `
@@ -113,13 +113,13 @@ jobs:
           -DREQUIRE_LUAJIT=TRUE  `
           -DRUN_IN_PLACE=${{ contains(matrix.type, 'portable') }} .
 
-      - name: Build Minetest
+      - name: Build
         run: cmake --build . --config Release
 
       - name: Unittests
         # need this workaround for stdout to work
         run: |
-          $proc = start .\bin\Release\minetest.exe --run-unittests -NoNewWindow -Wait -PassThru
+          $proc = start .\bin\Release\luanti.exe --run-unittests -NoNewWindow -Wait -PassThru
           exit $proc.ExitCode
         continue-on-error: true # FIXME!!