More flexibility dbus_proxy's naming + refactor of fdo proxies

This MR:

• adds attributes to dbus_proxy allowing users to:
  • disable/enable generation of blocking and asynchronous proxies.
  • control the naming scheme.
• changes the default naming scheme of dbus_proxy to:
  • remove Async prefix from asynchronous proxy name.
  • add Blocking suffix to blocking proxy name.
• Moves blocking fdo proxy types under blocking module.

Fixes #161 (closed).