STK used to have an app to create/read/update and delete themes. We should also provide the default site module with such an app.

There are additional information:

• theme support classes go to site module, theme-app goes to site-app module
• theme-app becomes a second subapp of the site app (like in security, mail or cache apps)
• theme-subapp will indeed be bootstrapped (in single file + bootstrap task in VH)
• site app will replace by site subapp (extra install task to guarantee ordering, renaming + tasks in VH)