Move main.js to source files dir

bin/com.github.rafostar.Clapper.in

@@ -9,4 +9,4 @@ Package.init({
   libdir: '@libdir@',
   datadir: '@datadir@',
 });
-Package.run(imports.main);
+Package.run(imports.clapper_src.main);

meson.build

@@ -23,6 +23,5 @@ installdir = join_paths(get_option('prefix'), 'share', meson.project_name())
 install_subdir('clapper_src', install_dir : installdir)
 install_subdir('css', install_dir : installdir)
 install_subdir('ui', install_dir : installdir)
-install_data('main.js', install_dir : installdir)
 
 meson.add_install_script('build-aux/meson/postinstall.py')