simplify demo code

[asaokamei]

simplify the PHP code in demo site.

• [x] remove NavBar.
• [x] remove breadcrumb.
• [x] remove twig templates (only plates).
• [x] no middleware (slim-tuum has example).
  • [x] remove CsRf check (slim-tuum has example).
  • [x] remove PhpDebugBar (add to slim-tuum as example).
  • [x] remove setting to Respond class.
• [ ] maybe use existing container, such as Pimple?
• [x] remove forge related code from Container; add provider for DocumentMap class.

[asaokamei]

using another container is too much for this demo. case closed.