Config Conversion: introduce resource.conf with global macros

refs #4701
Config Conversion: s/user_macros/global_macros/g
Config Conversion: Make ADMIN/USER macros global again (in resource.conf)

refs #4701
Config Conversion: Fix import removing inline comments after ';' and '#'.

fixes #4499
Config Conversion: Update sample icinga2 config.

refs #4701