nginx: fix problem with migration of uci conf template

nginx: fix problem with migration of uci conf template

Fix some problem with migration of uci conf template and include of
module.d directive.

Fix 2 case:
- uci.conf.template not versioned but with the include module.d
  resulting in double include module.d

- uci.conf.template version 1.1 with the include module.d at the end
  of the config. This is problematic for nginx as modules must be
  included before any http directive.

Handle this 2 case to restore a working uci.conf.template configuration
on migrated config.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>